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All questions of Human Health & Diseases for NEET Exam

The chemical test that is used for diagnosis of typhoid is:
  • a)
    ESR-Test
  • b)
    PCR-Test
  • c)
    Widal-Test
  • d)
    ELISA-Test
Correct answer is option 'C'. Can you explain this answer?

Jeeshan Ahmed answered
The Widal test is one method that may be used to help make a presumptive diagnosis of enteric fever, also known as typhoid fever.The test was based on demonstrating the presence of agglutinin (antibody) in the serum of an infected patient, against the H (flagellar) and O (somatic) antigens ofSalmonella typhi.

Can you explain the answer of this question below:
The disease chikunguniya is transmitted by
  • A:
    Cockroach
  • B:
    Aedes mosquitoes
  • C:
    House flies
  • D:
    Female Anopheles
The answer is b.

Rohan Singh answered
When a mosquito feeds on an infected person, the mosquito can become infected and can bite and infect others. The Aedes aegypti and Aedes albopictus mosquitoes transmit chikungunya. They also transmit dengue fever, another disease caused by a virus.

The disease causing microorganisms are called?
  • a)
    Microbes
  • b)
    Fungi
  • c)
    Allotropes
  • d)
    Pathogen
Correct answer is option 'D'. Can you explain this answer?

Anjali Iyer answered
Most microbes belong to four major groups: bacteria, viruses, protozoa or fungi. (To find out more, see the “Bacteria/Viruses/Protozoa” fact sheets). Disease-causing microbes can also be called pathogens, germs or bugs and are responsible for causing infectious diseases.

Which part of the tobacco plant is infected by Meloidogyne incognita ?
[2016]
  • a)
    Flower
  • b)
    Leaf
  • c)
    Stem
  • d)
    Root
Correct answer is option 'D'. Can you explain this answer?

Rhea Sarkar answered
(d) Meloidogyne incognita is a nematode (roundworm) in the family Heteroderidae. It is commonly called the "southern rootknot nematode" or the "cotton root-knot nematode".

Antibodies are produced by:
  • a)
    T-cells
  • b)
    B-cells
  • c)
    Monocytes
  • d)
    Phagocytes
Correct answer is option 'B'. Can you explain this answer?

Rohit Shah answered
Antibodies are produced by specialized white blood cells called B lymphocytes (or B cells). When an antigen binds to the B-cell surface, it stimulates the B cell to divide and mature into a group of identical cells called a clone.

Formation of antibodies within our body is called:
  • a)
    Innate immunity
  • b)
    Acquired immunity
  • c)
    Passive immunity
  • d)
    Active immunity
Correct answer is option 'D'. Can you explain this answer?

Shalini Basu answered
The combination of antibodies and complement promotes rapid clearing of pathogens. The production of antibodies by plasma cells in response to an antigen is called active immunity and describes the host's active response of theimmune system to an infection or to a vaccination.

The sporozoites that cause infection, when a female Anopheles mosquito bites a person, are stored in
  • a)
    Liver of person 
  • b)
    RBCs of mosquito
  • c)
    Salivary glands of mosquito
  • d)
    Intestine of person
Correct answer is option 'C'. Can you explain this answer?

Geetika Shah answered
  • Sporozoites enter the female Anopheles mosquito when they bite an infected person where these sporozoite fertilise and multiply in the stomach wall of the female Anopheles and stored in the salivary gland of mosquito till it is again transferred to the human body by a mosquito bite.
  •  After entering the human body the sporozoites reach the liver cells, where they multiply. This is followed by their attack on red blood cells resulting in their rupture. The ruptured RBCs release a toxin called haemozoin, which is responsible for high recurring fever, chills and shivering.
  • Mosquito Anatomy:

Immuno-deficiency syndrome could develop due to
  • a)
    Defective liver
  • b)
    AIDS virus
  • c)
    Defective thymus
  • d)
    Weak immune system
Correct answer is option 'B'. Can you explain this answer?

Rajeev Saxena answered
Human immunodeficiency virus infection and acquired immune deficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV).Following initial infection, a person may not notice any symptoms or may experience a brief period of influenza-like illness. Typically, this is followed by a prolonged period with no symptoms. As the infection progresses, it interferes more with the immune system, increasing the risk of developing common infections such as tuberculosis, as well as other opportunistic infections, and tumors that rarely affect people who have working immune systems.[5] These late symptoms of infection are referred to as acquired immunodeficiency syndrome (AIDS).This stage is often also associated with unintended weight loss.

Which one of the following is a matching pair of a drug and its category?
  • a)
    Heroin – psychotropic
  • b)
    Benzodiazepines – pain killer
  • c)
    Lysergic acid dimethyl amide – narcotic
  • d)
    Amphetamines – stimulant
Correct answer is option 'D'. Can you explain this answer?

Shivani Rane answered
Amphetamines is kind of drug which is used as stimulant. It is a strong CNS stimulant that is used in the treatment of ADHD. Lysergic acid dimethyl amide is not a narcotic and heroin is not a psychotropic agent.

Which of the following is the unit of immune system?
  • a)
    Chondrocyte
  • b)
    Erythrocyte
  • c)
    Lymphocyte
  • d)
    Parasite
Correct answer is option 'C'. Can you explain this answer?

Lymphocytes are one of several different types of white blood cells. Lymphocytes are of two types B cells and T cells. When a macrophage engulfs organisms, B cells (humoral immunity) release antibodies which cause the destruction of bacteria. The T cells (cell-mediated immunity) destroy the infectious organisms by killing the body cells that are affected. Hence lymphocytes is a unit of the immune system.
So, the correct answer is 'Lymphocytes'.

Anti venom against snake poison contains:
  • a)
    Antigens
  • b)
    Enzymes
  • c)
    Antigen-antibody complexes
  • d)
    Antibodies
Correct answer is option 'D'. Can you explain this answer?

Madhavan Ghosh answered
Anti venom against snake poison contains antibodies.

Explanation:
Anti venom is a serum that is used to treat snake bites. It contains antibodies that are specifically produced to neutralize the venom of a particular snake species. The antibodies are produced by injecting a small amount of the snake venom into an animal, usually a horse, and then collecting the blood serum from the animal after a certain period of time. This serum contains the antibodies that have been produced in response to the venom.

The antibodies in the anti venom work by binding to the venom molecules and neutralizing their toxic effects. This prevents the venom from causing damage to the body and allows the body's own immune system to clear the venom from the bloodstream.

It is important to note that anti venom is specific to the species of snake that produced the venom. This means that anti venom for one species of snake will not be effective against the venom of another species. It is also important to administer anti venom as soon as possible after a snake bite, as the venom can rapidly spread through the body and cause severe damage if left untreated.

The function of IgE is
  • a)
    Protection from inhaled/ingested pathogens
  • b)
    Mediate in allergic response
  • c)
    Activation of B-cells
  • d)
    Stimulation of complement system, passive immunity to foetus
Correct answer is option 'B'. Can you explain this answer?

Kiran Mehta answered
The function of IgE antibody as mediators in allergic reactions of Type I is explained by their ability to interact both with antigen and with receptor molecules on the membrane of blood basophils and tissue mast cells. However, it is not understood how the interaction of an allergen with cell-bound IgE antibody will induce basophil (mast) cells to release a great number of biologically active substances of which some will be further discussed at this meeting, nor is it known what role the IgE-mast cell system plays in the development and control of a normal immune response.

Which is the particular type of drug that is obtained from the plant whose one flowering branch is shown below?              [2014]
  • a)
    Hallucinogen
  • b)
    Depressant
  • c)
    Stimulant
  • d)
    Pain - killer
Correct answer is option 'A'. Can you explain this answer?

Charvi Shah answered
(a) The plant illustrated in diagram is Datura which has hallucinogenic properties. Hallucinogen is a substance that produces psychological effects normally associated only with dreams, schizophrenia, or religious visions. It produces changes in perception (ranging from distortions in what is sensed to perceptions of objects where there are none), thought, and feeling.

Japanese encephalitis is transmitted by
  • a)
    Tse tse fly
  • b)
    Sand fly
  • c)
    Housefly
  • d)
    Mosquito
Correct answer is option 'D'. Can you explain this answer?

Rajeev Saxena answered
Japanese encephalitis (JE) virus, a flavivirus, is closely related to West Nile and St. Louis encephalitis viruses. JE virus is transmitted to humans through the bite of infected Culex species mosquitoes, particularly Culex tritaeniorhynchus.

The virus is maintained in a cycle between mosquitoes and vertebrate hosts, primarily pigs and wading birds. Humans are incidental or dead-end hosts, because they usually do not develop high enough concentrations of JE virus in their bloodstreams to infect feeding mosquitoes.

JE virus transmission occurs primarily in rural agricultural areas, often associated with rice production and flooding irrigation. In some areas of Asia, these conditions can occur near urban centers.

In temperate areas of Asia, JE virus transmission is seasonal. Human disease usually peaks in the summer and fall. In the subtropics and tropics, transmission can occur year-round, often with a peak during the rainy season.

The primary and secondary immune response are carried out with the help of two special types of lymphocytes present in our blood called?
  • a)
    B-lymphocytes and T-lymphocytes
  • b)
    Lymphocytes and monocytes
  • c)
    T-lymphocytes and A-lymphocytes
  • d)
    B-lymphocytes and M-lymphocytes
Correct answer is option 'A'. Can you explain this answer?

The primary immune response can be described as the first response of our body system to a newly introduced foreign agent, while the secondary immune response is defined as an intensified immune response to this previously exposed antigen. The primary and secondary immune response is carried out by following two types of lymphocytes;

1)B-Lymphocytes: responsible for the production of antibodies in our blood. the type of antibodies is IgA. IgD, IgE, IgG, IgM.

2)T-Lymphocytes: These are mediators cell-mediated immunity.

So, the correct answer is 'Option A

Which of the following endoparasites of humans does show viviparity ?                          [2015 RS]
  • a)
    Enterobius vermicularis
  • b)
    Trichinella spiralis
  • c)
    Ascaris lumbricoides
  • d)
    Ancylostoma duodenale
Correct answer is option 'B'. Can you explain this answer?

Anagha Sharma answered
(b) Trichinella spiralis is an endoparasite found in human intestine. It is the smallest nematode producing larvae in large number. These larvae bore the intestine of human being and enter the blood and lymphatic systems.

Use of antihistamines and steroids give a quick relief from
[2009]
  • a)
    allergy 
  • b)
    nausea
  • c)
    cough
  • d)
    Headache
Correct answer is option 'A'. Can you explain this answer?

Aman Sharma answered
Allergy is the hypersensitiveness of a person to some foreign substances coming in contact with or entering the body. The common allergens are dust, pollen mould, spores, fabricates, bacteria, etc. During an allergic reaction, there is increased the release of histamine from mast cells. Use of antihistamines and from mast cells. Use of antihistamine and steroids give a quick relief from allergy.

Which one of the following statements is correct?
[2009]
  • a)
    Benign tumours show the property of metastasis.
  • b)
    Heroin accelerates body functions.
  • c)
    Malignant tumours ours may exhibit metastasis.
  • d)
    Patients who have undergone surgery are given cannabinoids to relieve pain.
Correct answer is option 'C'. Can you explain this answer?

Arnab Iyer answered
Malignant tumours may exhibit metastasis. Cancer (medical term: malignant neoplasm) is a class of diseases in which a group of cells display uncontrolled growth (division beyond the normal limits), invasion (intrusion on and destruction of adjacent tissues), and sometimes metastasis spread to other locations in the body via lymph or blood.

HIV that causes AIDS, first starts destroying:                       [2015 RS]
  • a)
    Leucocytes
  • b)
    Helper T- Lymphocytes
  • c)
    Thrombocytes
  • d)
    B- Lymphocytes
Correct answer is option 'B'. Can you explain this answer?

Rhea Sarkar answered
(b) After infection, HIV starts to destroy the Tcells (T-helper lymphocytes). T. cells are very important for the immune system. In the early stage of infection, the decline in numbers of T.cells is observed.

The antibody which can cross placental barrier is
  • a)
    IgA
  • b)
    IgE
  • c)
    IgM
  • d)
    IgG
Correct answer is option 'D'. Can you explain this answer?

Yash answered
IgG immunoglobin me sabse jyada 80% paye jate h . ye sbse chote imuno globin hote h kyuki enme paratopes kevel 2 hote h upr se ye monovalant hote h. chote size ke karan ye placenta ko cross kr jate h

Widal Test is carried out to test :
[2012]
  • a)
    Malaria
  • b)
    diabetes mellitus
  • c)
    HIV/AIdS
  • d)
    Typhoid fever
Correct answer is option 'D'. Can you explain this answer?

Sneha Basak answered
Widal test is carried out to test typhoid fever caused by Salmonella typhii bacteria. Typhoid vaccine is available.

Which of the following is a pair of viral diseases?
  • a)
    Ringworm, AIDS
  • b)
    Dysentery, Common Cold
  • c)
    Common Cold, AIDS
  • d)
    Typhoid, Tuberculosis
Correct answer is option 'C'. Can you explain this answer?

Muskan Sethi answered
Ringworm - fungal infection AIDS- HIV virus Common cold - Rhino Virus typhoid - Salmonella typhi ( bacteria) tuberculosis - mycobacterium tuberculosis ( bacteria) dysentery - it is of two types bacterial and amoebic therefore the viral diseases are AIDS and Common cold

Given below is the diagram of human lymphatic system, where A, B, C and D are lymphoid organs. Select incorrect option regarding the lymphoid organs labelled as A, B, C and D.
  • a)
    T cells mature in B
  • b)
    B and T cells undergo maturation in C
  • c)
    B and T cells undergo proliferation and differentiation in A
  • d)
    B cells mature in D
Correct answer is option 'B'. Can you explain this answer?

Lavanya Menon answered
'A'-lymph nodes, 'B'-Thymus, 'C'-spleen, 'D'-Bone marrow. Thymus and bone marrow are the primary lymphoid organs where maturation of T-cells and B-cells take place respectively. Lymph nodes and spleen are the secondary lymphoid organs where T-cells and B-cells undergo proliferation and differentiation.

Which of these glands is large at the time of birth but in adults, it reduces to a very small size?
  • a)
    Thyroid
  • b)
    Adrenal
  • c)
    Thymus
  • d)
    Spleen
Correct answer is option 'C'. Can you explain this answer?

Krithika Ahuja answered
Thymus gland is the correct option as it is large at the time of birth but reduces to a very small size in adults.

Explanation:

Thymus gland is a specialized gland of the lymphatic system that plays an important role in the development of the immune system. It is located in the upper thorax, behind the sternum, and in front of the heart. The thymus gland is large at the time of birth and continues to grow until puberty. After puberty, the thymus gland begins to shrink and is replaced by fatty tissue. By the age of 20, the thymus gland has reduced to about one-third of its maximum size, and by the age of 50, it has reduced to only a few grams of fatty tissue.

Why is Thymus gland large at the time of birth?

The thymus gland is very active during fetal development and plays a crucial role in the development of the immune system. The thymus gland produces T-lymphocytes, which are immune cells that play a crucial role in fighting infections and diseases. The thymus gland is essential for the development of T-lymphocytes, which are responsible for recognizing and attacking foreign substances in the body. The thymus gland is particularly important during fetal development because the fetus does not have a fully developed immune system and relies on the mother's immune system for protection.

Why does Thymus gland reduce in size in adults?

The thymus gland begins to shrink after puberty because the production of T-lymphocytes decreases with age. As a result, the thymus gland is no longer required to produce large numbers of T-lymphocytes, and its function gradually declines. The thymus gland is gradually replaced by fatty tissue, which is an irreversible process. However, the T-lymphocytes that are produced by the thymus gland during fetal development and childhood continue to circulate in the body and play a crucial role in the immune system throughout life.

The disease chikunguniya is transmitted by
  • a)
    Cockroach
  • b)
    Aedes mosquitoes
  • c)
    House flies
  • d)
    Female Anopheles
Correct answer is option 'B'. Can you explain this answer?

Abhay Iyer answered
Mosquitoes become infected when they feed on a person already infected with the virus. Infectedmosquitoes can then spread the virus to other people through bites. Chikungunya virus is most often spread to people by Aedes aegypti andAedes albopictus mosquitoes. These are the samemosquitoes that transmit dengue virus.

Which one of the following acts as a physiological barrier to the entry of microorganisms in the human body? 
  • a)
    Tears
  • b)
    Monocytes
  • c)
    Skin
  • d)
    Epithelium of urogenital tract
Correct answer is option 'A'. Can you explain this answer?

Arnab Iyer answered
Physiological barriers to the entry of microorganisms in the human body are tears in eyes, saliva in mouth and HCl in the stomach.The enzymes lysozymes are found in tears and saliva and inhibit the synthesis of peptidoglycan present in the cell wall of microorganisms especially eubacteria.

Several genes called _____have been identified in normal cells which when activated will turn in to ___ , and under certain conditions, could lead to cancerous transformation of the cells.
Complete the above paragraph by selecting correct sequence of words.
  • a)
    oncogenes, proto oncogenes
  • b)
    cellular oncogenes, proto oncogenes
  • c)
    proto oncogenes, oncogenes
  • d)
    cellular oncogenes, oncogenes
Correct answer is option 'C'. Can you explain this answer?

Prisha Chavan answered
Explanation:
Proto-oncogenes are normal genes in cells that regulate cell growth and division. However, if these genes are mutated or activated, they can become oncogenes, which promote uncontrolled cell growth and division, leading to the development of cancer. Several proto-oncogenes have been identified in normal cells, and when activated, they can turn into oncogenes, potentially leading to the transformation of the cells into cancer cells.

The correct sequence of words to complete the paragraph is "proto-oncogenes, oncogenes." The other options presented include "oncogenes, proto-oncogenes," "cellular oncogenes, proto-oncogenes," and "cellular oncogenes, oncogenes," but none of these accurately reflect the relationship between proto-oncogenes and oncogenes.

In summary, proto-oncogenes are normal genes that can become oncogenes if they are mutated or activated. Several proto-oncogenes have been identified in normal cells, and when activated, they can turn into oncogenes, which can lead to the development of cancer.

 Which one of the following immune system components does not correctly match with its respective role?
  • a)
    Interferons - secreted by virus-infected cells and protect non-infected cells from further viral infection
  • b)
    B- lymphocytes - produce antibodies in response to pathogens into blood to fight with them
  • c)
    Macrophages - mucus secreting cells that trap microbes entering in the body
  • d)
    IgA - present in colostrum in early days of lactation to protect infant from diseases
Correct answer is option 'C'. Can you explain this answer?

Ameya Majumdar answered
Incorrect Immune System Component and Role Match

Explanation:
The immune system is a complex network of cells, tissues, and organs that work together to defend the body against harmful pathogens. The immune system components and their respective roles are as follows:

a) Interferons - Secreted by virus-infected cells and protect non-infected cells from further viral infection. They stimulate the production of antiviral proteins that prevent the virus from replicating in healthy cells.

b) B-lymphocytes - Produce antibodies in response to pathogens into blood to fight with them. B-lymphocytes are a type of white blood cell that recognizes and neutralizes specific pathogens by producing antibodies that bind to and destroy them.

c) Macrophages - Mucus-secreting cells that trap microbes entering in the body. This is an incorrect match as macrophages are actually white blood cells that engulf and digest foreign substances, such as bacteria and viruses, in a process called phagocytosis.

d) IgA - Present in colostrum in early days of lactation to protect infant from diseases. IgA is an antibody that is found in secretions such as tears, saliva, and breast milk. It helps to prevent pathogens from entering the body through the mucous membranes.

In conclusion, the correct match of immune system components and their respective roles is important to understand the functioning of the immune system and to develop effective strategies to combat diseases.

The most abundant antibody produced against allergens is
  • a)
    lgE
  • b)
    IgA
  • c)
    IgC
  • d)
    IgM
Correct answer is option 'A'. Can you explain this answer?

Ankit Iyer answered
lgE is the most abundant antibody produced against allergens

Allergens are substances that can trigger an allergic response in individuals who are sensitive or allergic to them. When allergens enter the body, they can bind to specific antibodies called immunoglobulin E (IgE) antibodies. IgE antibodies are produced by a type of white blood cell called B cells in response to exposure to allergens. These antibodies are particularly involved in allergic reactions.

Explanation:
There are five major classes of antibodies, also known as immunoglobulins (Ig): IgA, IgD, IgE, IgG, and IgM. Each class of antibody has its own unique structure and function. Among these, IgE is the most abundant antibody produced against allergens.

Key Points:
- IgE is produced in response to allergen exposure.
- It plays a crucial role in allergic reactions by binding to allergens and triggering the release of chemicals such as histamine from mast cells and basophils.
- Histamine release leads to the typical symptoms of an allergic reaction, such as itching, swelling, redness, and increased mucus production.
- IgE antibodies are involved in allergic diseases such as allergic rhinitis (hay fever), asthma, and atopic dermatitis (eczema).
- The production of IgE antibodies is tightly regulated to prevent unnecessary allergic reactions.
- Individuals with allergies often have higher levels of IgE antibodies in their blood compared to non-allergic individuals.

Conclusion:
In summary, IgE is the most abundant antibody produced against allergens. It plays a key role in allergic reactions by binding to allergens and triggering the release of chemicals that cause allergy symptoms. Understanding the role of IgE antibodies in allergic reactions is important for the development of diagnostic tests and targeted treatments for allergies.

Which one of the following pairs of diseases is viral as well as transmitted by mosquitoes?
  • a)
    Encephalitis and sleeping sickness
  • b)
    Yellow fever and sleeping sickness
  • c)
    Elephantiasis and dengue
  • d)
    Yellow fever and dengue
Correct answer is option 'D'. Can you explain this answer?

Rishabh Verma answered
Yellow fever and dengue are the pair of diseases that are viral and transmitted by mosquitoes.

Yellow Fever:
- Yellow fever is a viral disease caused by the yellow fever virus.
- It is primarily transmitted by the bite of infected female mosquitoes, especially the Aedes aegypti species.
- The virus is endemic in tropical regions of Africa and Central and South America.
- Symptoms of yellow fever include fever, headache, muscle pain, jaundice, and bleeding.
- In severe cases, it can lead to organ failure and death.
- There is no specific treatment for yellow fever, but a vaccine is available for prevention.

Dengue:
- Dengue is a viral disease caused by the dengue virus.
- It is transmitted by the bite of infected female Aedes mosquitoes, primarily Aedes aegypti.
- Dengue is common in tropical and subtropical regions around the world.
- Symptoms of dengue include high fever, severe headache, joint and muscle pain, rash, and mild bleeding.
- In severe cases, it can lead to dengue hemorrhagic fever or dengue shock syndrome, which can be life-threatening.
- There is no specific treatment for dengue, but supportive care can help manage symptoms.

Viral Diseases Transmitted by Mosquitoes:
- Mosquitoes are known to transmit several viral diseases, including yellow fever, dengue fever, Zika virus, chikungunya, and West Nile virus.
- These viruses are primarily transmitted when a mosquito bites an infected person and then bites another person, transmitting the virus through its saliva.
- Mosquito-borne viral diseases are more common in tropical and subtropical regions where mosquito populations are abundant.
- The Aedes mosquitoes, particularly Aedes aegypti, are the main vectors for these viral diseases.

Conclusion:
- Among the given options, the pair of diseases that are both viral and transmitted by mosquitoes is yellow fever and dengue. Both diseases are caused by different viruses and are primarily transmitted by the bite of infected Aedes mosquitoes.

Which of the following pairs contains an infectious and a non-infectious disease respectively?
  • a)
    Typhoid and AIDS
  • b)
    AIDS  and cancer
  • c)
    Pneumonia and malaria
  • d)
    Cancer and malaria
Correct answer is option 'B'. Can you explain this answer?

Janani Bose answered
Infectious and Non-infectious Diseases

Infectious diseases are those that are caused by pathogenic microorganisms such as bacteria, viruses, fungi, and parasites. These diseases can be transmitted from one person to another through various modes of transmission such as direct contact, droplets, airborne, fecal-oral route, and vector-borne.

Non-infectious diseases are those that are not caused by pathogenic microorganisms. These diseases may have genetic, environmental, or lifestyle factors as their causes. Some examples of non-infectious diseases include cancer, diabetes, hypertension, and heart disease.

Answer Explanation

The pair that contains an infectious and a non-infectious disease respectively is option 'B', which is AIDS and cancer.

- AIDS is an infectious disease caused by the human immunodeficiency virus (HIV). It is primarily transmitted through sexual contact, blood transfusions, and vertical transmission from mother to child during pregnancy, childbirth, or breastfeeding.
- Cancer, on the other hand, is a non-infectious disease that is caused by uncontrolled growth and division of abnormal cells in the body. It can be caused by genetic mutations, exposure to environmental factors such as tobacco smoke and ultraviolet radiation, and lifestyle factors such as poor diet and lack of physical activity.

Therefore, option 'B' is the correct answer as it contains one infectious disease (AIDS) and one non-infectious disease (cancer).

Assertion: There is a time lag between the infection and appearance of first symptoms of AIDS.
Reason: This period may vary from a few months to many years up to 10 years.
  • a)
    Reason is correct but not explains the assertion
  • b)
    Both assertion and reason are correct.
  • c)
    Assertion is correct but reason is incorrect
  • d)
    Both assertion and reason are incorrect
Correct answer is option 'B'. Can you explain this answer?

Gaurav Kumar answered
The correct answer is:
2. Both assertion and reason are correct.
Explanation:
  • Assertion: There is a time lag between the infection and appearance of the first symptoms of AIDS.
    • This is correct. After an individual is infected with HIV, there is a period of latency where the virus is present but may not show symptoms. This time lag can vary greatly.
  • Reason: This period may vary from a few months to many years up to 10 years.
    • This is also correct. The asymptomatic period after HIV infection can range from a few months to several years, often up to 10 years or more before symptoms of AIDS manifest.
The reason accurately explains the assertion.

The letter T in T -lymphocyte refers to
[2009]
  • a)
    Thalamus
  • b)
    Tonsil
  • c)
    Thymus
  • d)
    Thyroid
Correct answer is option 'C'. Can you explain this answer?

Yash Saha answered
The letter T in T-lymphocyte refers to thymus. In human anatomy, the thymus is an organ located in the upper anterior portion of the chest cavity just behind the sternum. The thymus gland is a pink-grey organ that lies underneath the top of the breast bone.

The antigen binding site of an antibody is present at
  • a)
    the constant region
  • b)
    the C-terminal
  • c)
    the variable region
  • d)
    between constant and variable region
Correct answer is option 'C'. Can you explain this answer?

Mira Joshi answered
Antibodies are made up of four polypeptide chains two heavy and two light chains. Light and heavy chains are subdivided into variable and constant regions. The variable portion is used for binding to antigen and a constant portion determines its adherence and diffusivity.

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