Given below are two statements: one is labelled Assertion(A) and other is labelled Reason(R).

Assertion(A): The number of trophic levels in the grazing food chain usually will be 3 to 5.

Reason(R): An ecosystem follows first law of thermodynamics.

In the light of above statements, choose the correct answer from the options given below.

Most of the food chains are limited to three to five trophic levels. This is because at each trophic level some amount of energy is lost as heat. All the energy is not transferred to the next trophic level. The second law of thermodynamics states that whenever energy is distorted, there is a loss of energy through the release of heat. This occurs when energy is transferred between trophic levels as in a food web. When one animal feeds another, there is a loss of heat or energy in the process.

The First Law of Thermodynamics states that energy cannot be created or destroyed.