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

Options

A. I and ii
B. ii and iii
C. I and iii
D. iii and iv

Answer

B

Explanation

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