Question

Assertion(A): The number of trophic levels is restricted in grazing food chains

Reason (R): Energy transfer efficiency limits food chain lengths

• A. Both the assertion and reason are true and the reason is the correct explanation of the assertion
• B. Both the assertion and reason are true but the reason is not the correct explanation for the assertion
• C. The assertion is true but the reason is false
• D. Both assertion and the reason are false

Answer 1

The correct option is A Both the assertion and reason are true and the reason is the correct explanation of the assertion

Energy is transferred between various trophic levels when one organism eats another and obtains the energy-rich molecules.

As per 10 percent law, only 10 percent of energy is transferred from one trophic level to the next. This is because, at each trophic level, energy is lost in the form of heat as organisms carry out cellular respiration. Also, certain organic molecules cannot be digested by the organisms and hence are eliminated by the body rather than being used.

As the energy transferred from one trophic level to the next is not very high, there is too little energy left to support a population at a higher trophic level.

Therefore, the number of trophic levels is restricted in food chains.

Hence, both assertion and reason are true and the reason is the correct explanation of the assertion.