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Biology Assertion (A) & Reason (B) MCQ

MODEL PAPER 6 · CBSE STD 12 Science (CBSE - English Medium). 4 questions.

Questions

Assertion (A) & Reason (B) MCQ

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4 questions · timed · auto-graded

MCQ 11 Mark
Assertion (A): Evolution of man is the example of progressive evolution.
Reason (R): Tapeworm is developed due to retrogressive evolution.
  • 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: Progressive evolution is the formation of more complex specialized organisms from simple and less elaborate forms. Examples: evolution of amphibians from fish like ancestors and evolution of birds and mammals from reptile-like ancestors. Retrogressive evolution is the formation of simple and less elaborate forms from more complex and specialized ones. Example: evolution of many parasitic organisms like tapeworm which does not have digestive system. It absorbs food through body surface.
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MCQ 21 Mark
Assertion (A): Primer pheromones bring about physiological changes in the receivers.
Reason (R): Releaser pheromones cause immediate change in the receivers.
  • 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: Depending upon the changes that pheromones bring about in the receivers, they are of three types - primer, releaser and informer. Primer pheromones bring about physiological changes in the receivers. There is no immediate structural or behavioural effect. Pheromone present in the faeces of the adult locust is locustrol. It stimulates development in nymph locust. Releaser pheromones cause immediate change in the receiver animal, e.g., alarm pheromone of harvester ant, trail making pheromone of leaf cutter ants.
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MCQ 31 Mark
Assertion: Statins is a blood-cholesterol lowering agents.
Reason: It inhibiting the enzyme responsible for synthesis of cholesterol.
  • 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): Our laws permit legal adoption and it is as yet, one of the best methods for childless couples looking for parenthood.
Reason (R): Emotional, religious and social factors are also no deterrents in the legal adoption of orphaned and destitute children in India.
  • A
    Both Assertion and Reason are true, and Reason is the correct explanation of the Assertion.
  • B
    Both Assertion and Reason are true, but Reason is not the correct explanation of the Assertion.
  • C
    Assertion is true but Reason is false.
  • D
    Both Assertion and Reason are false.
Answer
Assertion is true but Reason is false.
Explanation: Assertion is true but Reason is false.
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