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Human Health and Disease MCQs
Class XII Biology
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NCERT Based
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NEET Practice
📘 Concept Based
📝 Exam Level
🤖 AI Explanations
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446 questions in this chapter
Question 31 of 446
📘 CLASS XII
Recent widespread incidences of dengue and chikungunya in many parts of India are linked to which mosquito vector?
Widespread incidences of the vector-borne (*Aedes* mosquitoes) diseases like dengue and chikungunya have been noted.
Question 32 of 446
📘 CLASS XII
The ability of the host to fight disease-causing organisms, conferred by the immune system, is called:
This overall ability of the host to fight the disease-causing organisms, conferred by the immune system is called immunity.
Question 33 of 446
📘 CLASS XII
Innate immunity is characterized by being:
Innate immunity is non-specific type of defence, that is present at the time of birth.
Question 34 of 446
📘 CLASS XII
Which component is an example of a physical barrier in innate immunity?
Skin on our body is the main physical barrier preventing entry of micro-organisms.
Question 35 of 446
📘 CLASS XII
Which of the following secretions acts as a physiological barrier preventing microbial growth?
Acid in the stomach, saliva in the mouth, tears from eyes—all prevent microbial growth.
Question 36 of 446
📘 CLASS XII
Which types of cells are classified as cellular barriers capable of phagocytosis?
Certain types of leukocytes like PMNL-neutrophils, monocytes and natural killer cells can phagocytose and destroy microbes.
Question 37 of 446
📘 CLASS XII
Virus-infected cells secrete proteins called interferons. These belong to which barrier category?
Virus-infected cells secrete proteins called interferons which are categorized as cytokine barriers.
Question 38 of 446
📘 CLASS XII
The second, highly intensified response elicited upon subsequent encounter with the same pathogen is called:
Subsequent encounter with the same pathogen elicits a highly intensified secondary or anamnestic response.
Question 39 of 446
📘 CLASS XII
The primary and secondary immune responses are carried out with the help of two special types of lymphocytes: T-lymphocytes and:
The responses are carried out with the help of B-lymphocytes and T-lymphocytes.
Question 40 of 446
📘 CLASS XII
The proteins produced by B-lymphocytes in response to pathogens are called:
The B-lymphocytes produce an army of proteins called antibodies to fight pathogens.
