question_answer 29)

  Which of the following limits the number of trophic levels in a food chain? (a) Decrease in energy at higher trophic levels   (b) Deficient food supply (c) Polluted air                                                                   (d) Water

Answer:

                  (a) Decrease in energy at higher trophic levels limits the number of trophic levels in a food chain. At each trophic level, a large portion of energy is utilized for the maintenance of organisms that occur at that trophic level. So, organism at higher level gets less and less energy at successive levels. The number of trophic levels are limited to 3-4 because after that, the energy available for the next level will be too small i.e., it will be insufficient to sustain life of the organisms.