Assertion (A) & Reason (B) MCQ

MCQ 11 Mark

Assertion: Gene flow increases genetic variations.
Reason : The random introduction of new alleles into the recipient population and their removal from the donor population affects allele frequency.

A
Assertion and reason both are correct statements and reason is correct explanation for assertion.
B
Assertion and reason both are correct statements but reason is not correct explanation for assertion.
C
Assertion is correct statement but reason is wrong statement.
D
Assertion is wrong statement but reason is correct statement.

Answer

Assertion and reason both are correct statements but reason is not correct explanation for assertion.
Explanation : Assertion and reason both are correct statements but reason is not correct explanation for assertion.

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MCQ 21 Mark

Assertion (A): The rate of decomposition is controlled by the chemical composition of detritus and climatic factors.
Reason (R): Warm and moist environment does not favour decomposition.

A
Both A and R are true and R is the correct explanation of A.
B
Both 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

A is true but R is false.
Explanation : A is true but R is false.

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MCQ 31 Mark

Assertion: Organ transplantation patients are given immunosuppressive drugs.
Reason : Transplanted tissue has antigens, which stimulate the specific immune response of the recipient.

A
Assertion and reason both are correct statements and reason is correct explanation for assertion.
B
Assertion and reason both are correct statements but reason is not correct explanation for assertion.
C
Assertion is correct statement but reason is wrong statement.
D
Assertion is wrong statement but reason is correct statement

Answer

Assertion and reason both are correct statements and reason is correct explanation for assertion.
Explanation : Assertion and reason both are correct statements and reason is correct explanation for assertion.

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MCQ 41 Mark

Assertion (A): Generally, a woman does not conceive during the lactation period.
Reason (R): The hormone 'prolactin initiates and maintains lactation in a postpartum woman.

A
Both A and R are true and R is the correct explanation of A.
B
Both 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

Both A and R are true but R is not the correct explanation of A
Explanation : Milk secretion is maintained as long as breast feeding, and hence hormone production continues. A woman does not conceive during the lactation period because lactation stimulates prolactin secretion and there is evidence that prolactin inhibits GnRH secretion, and antagonises the action of gonadotrophins on the ovaries. Ovulation is inhibited, and the ovaries are inactive, so estrogen and progesterone output falls to low levels. Thus during lactation a woman does not conceive. Only 5 -10% chances are there during lactation period. This can also be interpreted as mechanism devised by nature so that mother can look after the new born child by providing it with milk.

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Biology Assertion (A) & Reason (B) MCQ

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