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Biology & Human Body — UPSC Prelims Science & Environment previous year questions — page 3

213 solved previous year questions on Biology & Human Body, papers from 1993 to 2023, drawn from UPSC CSE Prelims, UPPCS, UPSC CDS. Each carries the printed answer key and the explanation from the source compilation.

1. #81UPSC CSE Prelims 2005
   Consider the following statements: I. Dengue is a protozoan disease transmitted by mosquitoes. 2. Retro-orbital pain is not a symptom of dengue. 3. Skin rash and bleeding from nose and gums are some of the symptoms of dengue.Which of the statements given above is/are correct?
   • A1 and 2 only
   • B3 only
   • C2 only
   • D1 and 3 only
   Answer: (B) 3 only
   Explanation

   Option b is the correct l is incorrect: Dengue is not a protozoan a viral disease caused by the dengue 2 is incorrect: Retro-orbital pain, or pain eyes, is one of the common symptoms of 3 is correct: Skin rash and bleeding from gums are some of the symptoms of severe known as dengue hemorrhagic fever or dengue Important Tips Dengue is caused by four types of viruses (DENV-1, DENV-2, DENV-3 and DENV-4) that belong to the genus Fla.vivirus. A person can be infected by any of these viruses more than once, but each infection gives lifelong immunity to that specific virus. Dengue is spread by the bite of female mosquitoes of the species Aedes aegypti and Aedes albopictus. These mosquitoes are active during the day and breed in containers of water, such as buckets, tires, vases and flower pots

2. #82UPSC CSE Prelims 2005
   Pneumoconiosis affects the workers who mainly in
   • ATanneries
   • BCoal mining industry
   • CDistilleries
   • DGlass Industry
   Answer: (B) Coal mining industry
   Explanation

   Option bis the correct is a lung disease that affects and other workers who breathe in certain kinds on the job. The disease includes asbestosis, silicosis workers' pneumoconiosis. Therefore, the correct Coal mining industry

3. #83UPSC CSE Prelims 2005
   Consider the following statements: Assertion (A): The person with diabetes insipidus feels thirsty. Reason A person with diabetes insipidus suffers from. excess secretion of vasopressin. Code
   • ABoth (A) and (R) are true, and (R) is the correct explanation of (A)
   • BBoth (A) and (R) are true, but (R) is not the correct explanation of (A)
   • C(A) is true, but (R) is false
   • D(A) is false, but (R) is true
   Answer: (C) (A) is true, but (R) is false
   Explanation

   Option c is the correct (A) is true: Diabetes insipidus is a rare causes the body to make too much urine and feel It is caused by problems with a hormone which helps the kidneys balance the amount in the body. Reason (R) is false: A person with diabetes insipidus suffer from excess secretion of vasopressin, but a lack of it or a resistance to it. Vasopressin the amount of urine produced by the kidneys, but insipidus, this function is impaired

4. #84UPSC CSE Prelims 2002
   Foot and Mouth disease in animals, a current epidemic in smne parts of the world, is caused by
   • ABacterium
   • BFungus
   • CProtozoan
   • DVirus
   Answer: (D) Virus
   Explanation

   Option d is the correct and mouth disease (FMD) in animals is caused aphthovirus, a member of the family are 7 serotypes of the virus, termed: A, 0, and SAT (Southern African Territories) 1, 2, and primarily affects cloven-hoofed animals of the The disease is characterized by high fever in the mouth and on the feet of animals

5. #85UPSC CSE Prelims 2002
   Consider the following statements: Assertion (A): Drinking of whiskey increases the frequency of urination. Reason Alcohol intake speeds up the secretion of vasopressin in the body. Code
   • ABoth (A) and (R) are true, and (R) is the correct explanation of (A)
   • BBoth (A) and (R) are true, but (R) is not the correct explanation of (A)
   • C(A) is true, but (R) is false
   • D(A) is false, but (R) is true
   Answer: (C) (A) is true, but (R) is false
   Explanation

   Option c is the correct (A) is true: Drinking of whiskey increases of urination because alcohol acts as a diuretic. is anything that makes you urinate (R) is false: Alcohol intake speeds up the secretion in the body is a false statement. Vasopressin, as antidiuretic hormone (ADH), is a hormone the kidneys to reabsorb water and reduce urine inhibits the release of ADH from the pituitary leads to increased urine production

6. #86UPSC CSE Prelims 2002
   When one gene control two or mo re different characters simultaneously, the phenomenon is called
   • AApomixis
   • BPleiotropy
   • CPolyploidy
   • DPolyteny
   Answer: (B) Pleiotropy
   Explanation

   Option b is the correct is a phenomenon in which a single gene multiple phenotypic traits. For example, the anaemia gene can affect both the shape of red and the ability of red blood cells to carry oxygen. Important Tips Apomixis: It is a type of asexual reproduction in which seeds are produced without fertilization. Polyploidy: It is a condition in which an organism has more than two sets of chromosomes. Polyteny: It is a condition in which chromosomes are abnormally large due to multiple rounds of DNA replication without cell division

7. #87UPSC CSE Prelims 2001
   'Athlete's Foot' is a disease caused by
   • ABacteria
   • BFungus
   • CProtozoan
   • DNematode
   Answer: (B) Fungus
   Explanation

   Option b is the correct foot is a disease caused by fungus. It is a type infection that usually affects the feet, especially toes. It can also spread to the toenails and the hands. contagious and can be acquired by direct contact with person or a contaminated surface. Important Tips Some of the common symptoms of athlete's foot are: Itching and soreness on the soles and between toes Burning or stinging sensation on the feet Blisters or cracks on the skin of the feet Scaling or peeling of the skin on the feet Discolored, thick, or crumbly toenails Foul odor from the feet

8. #88UPSC CSE Prelims 2001
   'Metastasis' is the process by which
   • ACells divide rapidly under the influence of drugs
   • BCancer cells spread through the blood or lymphatic system to other sites or organs
   • CThe chromosomes in cells nuclei are attached to the spindle before moving to the anaphase poles
   • DCancer cells are successfully inhibited to divide any further
   Answer: (B) Cancer cells spread through the blood or lymphatic system to other sites or organs
   Explanation

   Option b is the correct cells spread through the blood or lymphatic other sites or organs. This is the definition of is a process that allows cancer cells to break away original tumor and invade other parts of the body. Cells divide rapidly under the influence of drugs: This is not a specific process, but a general effect of some drugs on cell division. Some drugs can stimulate or inhibit cell division, depending on the type and dose of the drug The chromosomes in cells nuclei are attached to the spindle before moving to the anaphase poles: This is a description of metaphase, which is a stage of mitosis, the process of normal cell division. Cancer cells are successfully inhibited to divide any further: This is not a process, but a desired outcome of cancer treatment. Some methods of cancer treatment aim to stop or slow down the growth and spread of cancer cells j nmll

9. #89UPSC CSE Prelims 2001
   Assertion (A): Scientists can cut apart and paste together DNA molecules at will, regardless of the source of the molecules. Reason DNA fragments can be manipulated using restriction endonucleases and DNA ligases. Code
   • ABoth (A) and (R) are true and (R) is the correct explanation of (A)
   • BBoth (A) and (R) are true but (R) is not a correct explanation of (A)
   • C(A) is true but (R) is false
   • D(A) is false but (R) is true
   Answer: (A) Both (A) and (R) are true and (R) is the correct explanation of (A)
   Explanation

   Option a is the correct answer. Assertion (A) is true- Scientists can cut apart and paste together DNA molecules at will, regardless of the source of the molecules using restriction endonucleases and DNA ligases. Reason (R) is true, and (R) is the correct explanation of Restriction endonucleases are enzymes that cut DNA at specific sequences. DNA ligases are enzymes that join DNA fragments together

10. #90UPSC CSE Prelims 2001
    The American multinational company, Monsanto, has produced an insect-resistant cotton variety that is undergoing field trials in India. A toxin gene from which one of the following bacteria has been transferred to this transgenic cotton?
    • ABacillus subtilis
    • BBacillus thuringiensis
    • CBacillus amyloliquifaciens
    • DBacillus globlii
    Answer: (B) Bacillus thuringiensis
    Explanation

    Option b is the correct answer. Bacillus thuringiensis (Bt) is a bacterium that produces a protein crystal that is toxic to certain insects. This protein crystal is called the crystal protein toxin (Cry protein). Monsanto's insect-resistant cotton variety, Bollgard, contains a Cry protein gene from Bt. When the Bt Cry protein is expressed in the cotton plant, it makes the plant resistant to certain insect pests, such as bollworms and budworms

11. #91UPSC CSE Prelims 2000
    The blood glucose level is commonly expressed as
    • Amm of Hg
    • BMilligram per decilitre
    • CParts per million
    • DGram per litre
    Answer: (B) Milligram per decilitre
    Explanation

    Option b is the correct blood glucose level is the measure of the amount in the blood. It is commonly expressed as decilitre A normal fasting blood sugar level 70 and 99 A normal blood sugar level after eating is less than 140 Important Tips Some other units that are used to measure different quantities are: mm of Hg: This is used to measure the blood pressure level. It stands for millimeters of mercury. Parts per million: This is used to measure the concentration of a contaminant in soils and sediments. Gram per litre: This is used to measure mass concentration

12. #92UPSC CSE Prelims 2000
    Hybridoma technology is a new biotechnological approach for commercial production of
    • AMonoclonal antibodies
    • BInterferon
    • CAntibiotics
    • DAlcohol
    Answer: (A) Monoclonal antibodies
    Explanation

    Option a is the correct technology is a technique that can be used monoclonal antibodies. Monoclonal antibodies that are all identical to each other. They by hybrid cells called hybridomas. Hybridomas by fusing a B lymphocyte that produces a with a myeloma cell, which is a type of cancer cell

13. #93UPSC CSE Prelims 2000
    Assertion (A): 'DNA Fingerprinting' has become a powerful tool to establish paternity and identity of criminals in rape and assault cases. Reason Trace evidence such as hairs, saliva and dried semen are adequate for DNA analysis. Code
    • ABoth (A) and (R) are true and (R) is the correct explanation of (A)
    • B(A) Both (and (R) are true but (R) is not a correct explanation of (A)
    • C(A) is true but (R) is false
    • D(A) is false but (R) is true
    Answer: (A) Both (A) and (R) are true and (R) is the correct explanation of (A)
    Explanation

    Option a is the correct (A) is true- DNA fingerprinting can be establish paternity by comparing the DNA of a the DNA of the alleged father. If the DNA of the the alleged father match, then it is highly likely alleged father is the biological father of the child. can also be used to identify criminals in assault cases by comparing the DNA of a crime to the DNA of a suspect. If the DNA of the sample and the suspect match, then it is highly the suspect was at the crime (R) is true, and (R) is the correct explanation Trace evidence is any evidence that is left at a that is too small to be seen with the naked eye Examples of trace evidence include hairs, saliva, and Trace evidence can be used for DNA analysis is a very stable molecule and can be preserved for of time, even in harsh conditions

14. #94UPSC CSE Prelims 1999
    Lathyrism is caused by excessive consumption of
    • AKhesari dal
    • BMustard oil
    • CPolished rice
    • DMushrooms
    Answer: (A) Khesari dal
    Explanation

    Option a is the correct is caused by excessive consumption of Lathyrism is a neurological disorder caused by eating of Lathyrus sativus, also known as grass pea, or khesari dal. It affects the cross-linking of protein in connective tissues, causing muscle brittle bones. It is also known as the oldest and is banned in many parts of India

15. #95UPSC CSE Prelims 1999
    Assertion (A): Dolly was the first cloned mammal. Reason Dolly was produced by in-vitro fertilization. Code
    • ABoth (A) and (R) are true and (R) is the correct explanation of (A)
    • BBoth (A) and (R) are true but (R) is not correct explanation of (A)
    • C(A) is true but (R) is false
    • D(A) is false but (R) is true
    Answer: (C) (A) is true but (R) is false
    Explanation

    Option c is the correct (A) is true- Dolly was the first cloned was a female Finn Dorset sheep born on July 5, lived for six years and died on February 14, 2003, lung disease. She is buried at the Roslin Edinburgh, Scotland, where she was (R) is false- Dolly was not produced by (IVF). IVF is a process of fertilization an egg and sperm outside the body. Dolly using a process called somatic cell nuclear which involves transferring the nucleus of cell (a non-reproductive cell) into an cell (an egg cell that has had its nucleus removed)

16. #96UPSC CSE Prelims 1996
    Consider the following statements:AIDS is transmitted: 1. By sexual intercourse 2. By blood transfusion 3. By mosquitoes and other blood sucking insects 4. Across the placenta Code
    • A1, 2 and 3 are correct
    • B1, 2 and 4 are correct
    • C1, 3 and 4 are correct
    • D1 and 3 are correct
    Answer: (B) 1, 2 and 4 are correct
    Explanation

    ranked 10 among countries with the largest number Option b is the correct answer. underweight children and ranked 17 for the highest is caused by the human immunodeficiency virus of stunted children in the world. The most that weakens the immune system and makes the nutritional problems in India are vitamin vitamin vulnerable to various infections and diseases. HIV vitamin vitamin B 12, protein, iron, iodine, and folate be transmitted through: Among these, vitamin A deficiency is one of the most Sexual contact with an infected person without using a serious and widespread problems in India. Vitamin condom or taking medicines to prevent or treat HIV. A is essential for healthy eyesight, strong immunity, Blood transfusion or sharing of injection drug equipment and cell development. Vitamin A deficiency can cause with an infected person because these may have blood xerophthalmia, a conditio

17. #97UPSC CSE Prelims 1996
    Which of the following are associated with diabetes mellitus, a common disease in adults? 1. Higher sugar level in blood 2. Lower sugar level in blood 3. Lower insulin level in blood 4. Higher insulin level in blood Code
    • A2 and 4 only
    • B1 and 2 only
    • C2 and 3 only
    • D1 and 3 only
    Answer: (D) 1 and 3 only
    Explanation

    dioxin, used as a defoliant. Agent Orange was a herbicide and defoliant used by the United States military Option d is the correct answer. the Vietnam War (1955-1975). It was a mixture of mellitus is a condition where there is too much herbicides, acid (2,4-D) in the blood. Glucose is an important source of acid (2,4,5-T). The for the cells and the brain. Insulin is a hormone that contained a contaminant called dioxin, which is a glucose enter the cells and lowers the blood glucose toxic and persistent organic pollutant. Dioxin has linked to a number of health problems, including sugar level in blood and lower insulin level in birth defects, and immune system disorders. It is also are both associated with diabetes mellitus. Lower suspected carcinogen. Important Tips Short summary of Vietnam War: Event Date French defeat at Dien Bien Phu 1954 The French are defeated by the Viet Minh, lead

18. #98UPSC CSE Prelims 1995
    Which one of the following sets is correctly matched?
    • ADiphtheria, Pneumonia and Leprosy - Sex-linked
    • BAIDS, Syphilis and Gonorrhoea - Bacterial
    • CColour blindness, Haemophilia and Sickle cell anaemia - Hereditary
    • DPolio, Japanese B encephalitis and Plague - Viral
    Answer: (C) Colour blindness, Haemophilia and Sickle cell anaemia - Hereditary
    Explanation

    Phenylketonuria is an example of an inborn error of metabolism. This 'error' refers to inherited lack of Option c is the correct answer. blindness, Haemophilia and Sickle cell anaemia Phenylketonuria (PKU) is a rare inherited disorder genetic disorders. Colour blindness and Haemophilia causes an amino acid called phenylalanine to build up sex-linked, meaning they are inherited through the X the body. PKU is caused by a change in the Sickle cell anaemia is autosomal, meaning it is hydroxylase (PAH) gene, which helps create the through any chromosome other than X or Y. needed to break down phenylalanine. Without the enzyme Diphtheria, Pneumonia and Leprosy are bacterial necessary to break down phenylalanine, a dangerous buildup diseases, not sex-linked. can develop when a person with PKU eats foods that contain protein or aspartame, an artificial sweetener. AIDS, Syphilis and Gonorrhoea ar

19. #99UPSC CSE Prelims 1995
    "It begins as a single cell and grows into a merciless disease that claims millions of lives year after year. But scientists are steadily unlocking its mysteries and the fight against it may now have reached a dramatic turning point. New discoveries promise better therapies and hope in the the above quotation is
    • ACancer
    • BAIDS
    • CTuberculosis
    • DAlzheimer's disease
    Answer: (A) Cancer
    Explanation

    females who inherit one copy will be carriers and may or Option a is the correct answer. not have mild symptoms. Females who inherit two copies disease referred to in the above quotation is cancer. the mutated gene will also develop the disease, but this is a group of diseases that involve abnormal cell very with the potential to invade or spread to other parts 190. Solution: the body. Scientists are constantly researching new prevent, diagnose, and treat cancer, and some of the recent Exp) Option b is the correct include immunotherapy, targeted therapy, A heart attack, or myocardial infarction, occurs when biopsy, and nanomedicine. flow of blood to the heart is severely reduced or blocked due to a buildup of fat, cholesterol and other substances in the

20. #100UPSC CSE Prelims 1993
    Due to unsafe drinking water and lack of Sanitation, three main communicable diseases in developing countries are
    • ADiarrhoea, cancer, gout
    • BMalaria, Acute diarrhoea, Schistosomiasis
    • COrchociasis, white blindness, arthritis
    • DRheumatism, Malaria, AIDS
    Answer: (B) Malaria, Acute diarrhoea, Schistosomiasis
    Explanation

    Option b is the correct to the World Health Organization (WHO), main communicable diseases in developing to unsafe drinking water and lack of sanitation are: Diarrhoea: Diarrhoea is the fifth leading cause of death in children younger than 5 years old and is caused by germs that contaminate water and food. Diarrhoea can lead to dehydration, malnutrition, and stunted growth. Malaria: Malaria is a mosquito-borne disease that affects millions of people every year, especially in Africa. Malaria is transmitted by the bite of an infected female Anopheles mosquito, which breeds in stagnant water sources such as ponds, puddles, and rice fields. Malaria can cause fever, headache, chills, and severe complications such as anemia, organ failure, and Schistosomiasis: Schistosomiasis is a parasitic infection that affects over 200 million people worldwide, mostly in sub-Saharan Africa. Schistosomiasis

21. #101UPSC CSE Prelims 1993
    Haemophilia is a genetic disease carried by
    • AWomen appear in women
    • BWomen, appear in men ifal
    • CMen appear in women
    • DMen appear in men
    Answer: (B) Women, appear in men ifal
    Explanation

    Option b is the correct is a genetic disorder that impairs ability to make blood clots, a process needed bleeding. It is usually inherited from one's an X chromosome carrying a nonfunctional genes for clotting factors VIII and IX are located X chromosome, so males have only one copy of while females have two copies. This means that if inherits a haemophilia allele (a variant of the gene) only X chromosome, he will have the disorder. A a haemophilia allele on one X chromosome usually normal allele on her other X chromosome that can clotting factor, so she has some protection haemophilia. A female with one haemophilia one normal allele is called a the correct answer to the question is (b) Women are the carrier of the disease and it appears This is because women can carry the haemophilia pass it on to their sons, who will have haemophilia

22. #102UPSC CSE Prelims 1993
    Which one of the following seeds can benefit a patient of diabetes mellitus by normalizing his blood sugar level?
    • ACoriander seeds
    • BMustard seeds
    • CCumin seeds
    • DFenugreek seeds
    Answer: (D) Fenugreek seeds
    Explanation

    Option d is the correct seeds can benefit a patient of diabetes normalizing his blood sugar level. Fenugreek folic acid, sodium, zinc, magnesium, copper, carotene, etc that help in controlling diabetes as cholesterol levels in the body. Having one ground or powdered fenugreek seed added in water fruitful for diabetics

23. #103UPPCS 2022
    Sulpha drug is which of the following types of drugs?
    • AAnalgesics
    • BAntibacterial
    • CAntiseptic
    • DAntipyretic
    Answer: (B) Antibacterial
    Explanation

    Option b is the correct drug is Antibacterial drug. Sulpha drugs are a synthetic medicines that contain the sulfonamide They are also called sulfa drugs or drugs are mainly used to treat infections caused such as urinary tract infections, ear infections, drugs work by binding and inhibiting a specific is essential for the synthesis of folate, a vitamin need to grow and multiply. By blocking this drugs prevent the bacteria from making new DNA and eventually kill them

24. #104UPPCS 2021
    Which of the following is not mosquito borne disease?
    • ADengue fever
    • BFilariasis
    • CSleeping sickness
    • DMalaria
    Answer: (C) Sleeping sickness
    Explanation

    Option c is the correct sickness, also known as human is not a mosquito-borne disease. It by a parasite called Trypanosoma brucei, which by the bite of an infected tsetse fly. According World Health Organization, mosquito-borne diseases illnesses caused by parasites, viruses and bacteria transmitted by mosquitoes. Some of the most diseases include malaria, dengue, chikungunya, Zika fever and filariasis

25. #105UPPCS 2003
    Consider the following effects of genetic engineering: 1. Disease resistance 2. Growth promotion 3. Animal cloning 4. Human cloning Of the above, that have been tried with a certain amount of success include
    • A1, 3 and 4
    • B2, 3 and 4
    • C1, 2 and 4
    • D1, 2 and 3
    Answer: (D) 1, 2 and 3
    Explanation

    Option d is the correct I is correct- Scientists have genetically to be resistant to pests and diseases. For example, is genetically engineered to produce a protein that to insects. This helps to protect corn crops from 2 is correct- Scientists have genetically to grow faster and produce more meat or milk. some salmon have been genetically engineered faster than wild 3 is correct- Scientists have cloned a variety including sheep, cows, pigs, and goats. Dolly was the first mammal to be cloned. be used to produce animals with desirable traits, such milk production or resistance to 4 is incorrect- Human cloning has not yet achieved. There are ethical concerns cloning, and it is also technically challenging. Important Tips Genetic Description Examples Disorder Category Single gene Disorders caused Huntington's disorders by defects in disease, cystic one particular fibrosis, sickle gene, ofte

26. #106Previous year
    Consider the following statements:(CAPF 2022) 1. Mirage 2000 is a twin-engine fighter jet. 2. HAL Tejas is a delta-winged fighter jet. 3. Rafale is a hypersonic fighter jet.Which of the statements given above is/are correct?
    • A1 and 2
    • B2 only
    • C1 and 3
    • D3 only
    Answer: (B) 2 only
    Explanation

    Option b is the correct answer The Dassault Mirage 2000 is a French multirole, single engine, fourth-generation jet fighter manufactured by Dassault Aviation. The HAL Tejas ("Brilliance") is an Indian, single engine, delta wing, light multirole fighter. The Dassault Rafale is a French twin-engine, canard delta wing, multirole fighter aircraft designed and built by Dassault Aviation. The Rafale is a supersonic fighter jet. It can reach speeds ofup to Mach 1.8 (1,235 mph or 1,984 km/h). However, it is not a hypersonic fighter jet. A hypersonic fighter jet is capable of flying at speeds of Mach 5 or more (3,836 mph or 6,174 km/h)

27. #107UPSC CAPF 2021
    Which one of the following diseases does not transmit through fine droplets coming out from mouth or nose of an infected person?
    • APneumonia
    • BCOVID-19
    • CHIV-AIDS
    • DTuberculosis
    Answer: (C) HIV-AIDS
    Explanation

    Option c is the correct is a disease that is transmitted through infected blood, semen, vaginal fluids, or breast milk. It transmitted through respiratory droplets. and tuberculosis, are all respiratory can be transmitted through respiratory r

28. #108UPSC CAPF 2016
    Which one of the following statements regarding Zika virus is not correct?
    • AIt was first isolated from a monkey in the Zika forest of Uganda
    • BIt is transmitted by daytime active Aedes mosquitoes
    • CIt does not cause mother to child infection
    • DZika virus in pregnant women results in abnormal brain development of the fetus
    Answer: (C) It does not cause mother to child infection
    Explanation

    Option c is the correct virus can he transmitted from a pregnant woman fetus during pregnancy or around the time of can result in serious birth defects, such as small head size) and other as well as preterm birth and miscarriage. It was first isolated from a monkey in the Zika forest of Uganda is correct, because it is based on the historical discovery of the virus in 1947 by researchers studying yellow fever in a rhesus monkey in the Zika forest near Entebbe, Uganda. It is transmitted by daytime-active Aedes mosquitoes is correct, because it is based on the main mode of transmission of the virus by the bite of infected Aedes species mosquitoes, especially Aedes aegypti and Aedes albopictus, which are active mostly during the day. These are the same mosquitoes that transmit dengue, chikungunya and yellow fever. Zika virus in pregnant women results in abnormal brain development of the fet

29. #109UPSC CDS 2020
    Which one of the following is not an epidemic disease?
    • ACholera
    • BSmallpox
    • CMalaria
    • DElephantiasis tunlm
    Answer: (D) Elephantiasis tunlm
    Explanation

    Option d is the correct also known as lymphatic filariasis, is disease caused by infection with filarial by mosquito bites. Elephantiasis is not disease because it is not contagious. The diseases, cholera, malaria, and smallpox, are and can spread from person to person, epidemic diseases. Important Tips Cholera is an acute diarrheal illness caused by infection with the bacterium Vibrio cholerae. It is transmitted through contaminated food or water. Smallpox is a highly contagious viral disease that was once one of the most feared diseases in the world. It is caused by the variola virus. Malaria is a mosquito-borne parasitic disease that is caused by Plasmodium parasites. There are five species of Plasmodium that can infect humans, and each species causes a different type of malaria

30. #110UPSC CDS 2015
    Measles is a disease caused by
    • Abacteria
    • Bvirus
    • Cprotozoan
    • Dworm
    Answer: (B) virus
    Explanation

    Option bis the correct also known as rubeola, is a highly infection caused by the measles virus. It is person to person through respiratory droplets from individual. Measles primarily affects the and can lead to a range of symptoms, including cough, runny nose, red eyes, and a characteristic spreads across the body

31. #111State PCS 2018
    When customers of a website are unable to access it due to flooding of fake network traffic, it is known as
    • Avirus
    • BTrojan horse
    • Ccracking
    • Ddenial of service attack
    Answer: (D) denial of service attack
    Explanation

    Option d is the correct customers of a website are unable to access it due of fake network traffic, it is known as attack. A denial-of-service attack is a type of cyber attack in which a malicious actor aims to render a network resource unavailable to its intended users or indefinitely disrupting the services of a to a denial-of-service attack typically functions or flooding a targeted machine or superfluous requests in an attempt to overload prevent some or all legitimate requests from A denial-of-service attack is different from a Trojan horse, or a cracking, which are other types of cyber attacks that involve infecting, compromising, or accessing without authorization

32. #112State PCS 2014
    Firewall is used in Communication Network/system for protection from
    • AUnauthorized attack
    • BData driven attack
    • CFire attack
    • DVirus attack
    Answer: (A) Unauthorized attack
    Explanation

    Option a is the correct firewall is used in communication network/system from unauthorized attack, data driven virus attack. A firewall is a network security device incoming and outgoing network traffic and blocks data packets based on a set of security rules

33. #113State PCS 1999
    The organ affected by malaria is
    • AHeart
    • BLungs
    • CKidney
    • DSpleen
    Answer: (D) Spleen
    Explanation

    Option d is the correct organ affected by malaria is the spleen. The an organ that acts primarily as a blood filter and roles in regard to red blood cells and the Malaria is a disease caused by a parasite that blood cells and can cause damage to the spleen. can become enlarged (splenomegaly) or ruptured malaria infection

34. #114State PCS 2013
    Steps of Recombinant DNA technology are given below: A. Identification and isolation of the genetic material. B. Fragmentation of DNA. C. Obtaining the foreign gene product. D. Downstream processing. E. Ligation of DNA fragmentation into the vector. F. Isolation of desired DNA fragments. G. Amplification of gene of interest. H. Transfer of Recombinant DNA into the host cell/ organism. The correct sequence of steps is
    • AC - A - B - D - E - F - G - H
    • BA - D - C - B - E - G - F - H
    • CA - B - F - G - E - H - c-D
    • DH-F-G-E-A-D-B-C
    Answer: (C) A - B - F - G - E - H - c-D
    Explanation

    Option c is the correct correct sequence is explanation of each step: Identification and isolation of the genetic material This involves identifying the gene of interest and isolating it from the donor organism. This can be done using a variety of methods, such as screening a genomic library or Fragmentation of DNA This involves cutting the DNA into fragments using restriction enzymes. Restriction enzymes are enzymes that recognize specific sequences of DNA and cut at those Isolation of desired DNA fragments This involves isolating the gene of interest from the other DNA fragments. This can be done using a variety of methods, such as gel electrophoresis or DNA Amplification of gene of interest This involves making copies of the gene of interest using PCR. PCR is a technique that can be used to amplify any DNA sequence, including genes. Important Brief comparison between DNA and RNA: Suga

35. #115State PCS 2007
    Which one of the following statements is not true with regard to the transplantation of stem cells in animals?
    • AThey multiply themselves throughout the life span of an animal
    • BThey repair the damaged tissues of the organs
    • CThey have the capacity to produce one or more types of specialized cells
    • DThey are found only in the embryo
    Answer: (D) They are found only in the embryo
    Explanation

    Option d is the correct cells are found in both embryos and adults. cells are derived from embryos that are 3-5 days are pluripotent, which means that they can any type of cell in the body. Adult stem cells are a variety of tissues in the body. They are means that they can develop into a limited different types of cells. Adult stem cells can be the blood and bone marrow of an adult. Ligation of DNA fragmentation into the vector This involves joining the gene of interest to a cloning vector. Cloning vectors are small pieces of DNA that can be used to carry foreign genes into host Transfer of Recombinant DNA into the host cell/ organism This involves introducing the recombinant DNA into a host cell. Host cells are typically bacteria, yeast, or animal Obtaining the foreign gene product This involves expressing the gene of interest in the host cell and obtaining the recombinant protein. This

36. #116State PCS 1999
    Down syndrome is a genetic disorder, which is caused due to
    • ADue to changes in the number of the chromosomes
    • BDue to changes in the structure of the chromosome
    • CDue to changes in the structure of D.N.A
    • DDue to changes in the structure of R.N.A
    Answer: (A) Due to changes in the number of the chromosomes
    Explanation

    Option a is the correct syndrome is a genetic disorder caused by an of chromosome 21 in some or all of the cells in This extra genetic material affects the physical development of the person with Down syndrome is a genetic disorder, which is caused changes in the number of chromosomes. This is cases of Down syndrome are caused by trisomy means the person has three copies of instead of two. This is a result of a random error in called nondisjunction

37. #117State PCS 1998
    If albumin is releasing with urine, then the failure of which organ may occur?
    • ALiver
    • BKidney
    • CHeart
    • DSpleen
    Answer: (B) Kidney
    Explanation

    Option bis the correct is a type of protein that circulates in your helps with many functions in your body. do not allow albumin to pass into your urine, your kidneys are damaged, albumin can leak through and cause albuminuria. Albuminuria is a many types of kidney disease and a risk factor diagnose albuminuria, doctors use a urine test the ratio of albumin to creatinine amount of albumin in your urine is less than 30 above 30 mg/g may mean you have kidney if your estimated glomerular filtration rate 60 or of the common causes of kidney damage that to albuminuria are diabetes, high blood pressure, and glomerular disease. Albuminuria can also higher risk of developing various cardiovascular diseases

38. #118State PCS 2002
    Consider the following statements: Assertion (A): Immune system gets affected by AIDS. Reason T-lymphocytes get completely damaged in AIDS. Select the correct answer using the code given below
    • A(A) is correct but (R) is not the correct explanation of (A)
    • B(A) is correct and (R) is the correct explanation of (A)
    • C(A) is correct but (R) is wrong
    • D(A) is wrong but (R) is correct
    Answer: (B) (A) is correct and (R) is the correct explanation of (A)
    Explanation

    Reason (R) is the correct explanation of Assertion Option b is the correct answer. T-lymphocytes are also called CD4 cells or helper (A) is correct: AIDS stands for acquired They are vital players in the regulation of immune syndrome, which is the most to invading microorganisms. HIV targets these cells stage of HIV infection. HIV stands for human destroys them or damages them so that they cannot virus, which attacks the body's immune properly. Without treatment, HIV typically turns into especially the CD4 cells or T-lymphocytes. The in about to 10 years. At this stage, the immune system system prevents the body from acquiring diseases severely damaged, and the risk of contracting infections that come its way. As HIV gradually weakens infections is much greater. AIDS is not diagnosed until immune system, it makes it easier to get sick with wouldn't usually cause illness in a person with

39. #119UPSC CSE Prelims 2013
    Which of the following adds/add nitrogen to the soil? 1. Excretion of urea by animals 2. Burning of coal by man 3. Death of vegetationSelect the correct answer using the codes given below
    • A1 only
    • B2 and 3 only
    • C1 and 3 only
    • D1, 2 and 3
    Answer: (C) 1 and 3 only
    Explanation

    Option c is the correct 1 and 3 are correct: Nitrogen is the of Urea. When plants die, down, or decompose, dead plant cells. During about plant matter, organic nitrogen is converted to inorganic ammonium and released 2 is incorrect: Burning of coal does not to soil, but it releases oxides of nitrogen into

40. #120UPPCS 2020
    Generally, environment can be classified as following categories. Which among the following is not a part of such category?
    • AOperational Environment
    • BPhysical Environment
    • CCultural Environment
    • DBiological Environment
    Answer: (B) Physical Environment
    Explanation

    Option b is the correct insurance for individuals in India generally following l is correct: Cost of restoration of the in case of malware disrupting access to This includes the expenses incurred for restoring data or computer programs that are corrupted due to a cyber 2 is incorrect: Cyber insurance for individuals generally does not cover the cost of a new some miscreant willfully damages it, if proved so. because cyber insurance only covers losses arising not physical damage to the computer 3 is correct: Cost of hiring a specialized minimize the loss in case of cyber extortion. This fees paid to a professional firm or person approved by to prevent or mitigate a cyber extortion threat. 4 is correct: Cost of defense in the Court of Law third-party files a suit. This includes the legal costs incurred with the insurer's consent for legal action brought by a third-party against the as a re

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