Question

Study the following statements regarding food chains and select the correct ones.
(i) Removal of $80\%$ tigers from an area resulted in greatly increased growth of vegetation.
(ii) Removal of most of the carnivores resulted in an increased population of deers.
(iii) The length of food chains is generally limited to $3-4$ trophic levels due to energy loss.
(iv) The length of food chains may vary from $2$ to $8$ trophic levels.

• A. (i) and (ii)
• B. (ii) and (iii)
• C. (i) and (iii)
• D. (iii) and (iv)

Answer 1

The correct option is B (ii) and (iii)

If carnivores, which feed on deer are removed, then the deer population will flourish. Removal of 80% of tigers from an area will cause an increase in the population of herbivores, which would further feed on more vegetation thus, decreasing its growth. The length of the food chain is limited to 3−4 trophic levels as only 10% of energy is transferred to the next trophic level. Hence after 3−4 trophic levels, there is very little or no energy left to sustain more trophic levels.

So, the correct answer is '(ii) and (iii)'.