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MODEL PAPER 6 — BIOLOGY STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceBIOLOGYMODEL PAPER 61 Mark
MCQ
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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