What is the major reason for a food chain to have limited trophic levels of 3-4 only?
Energy loss at each level
10% is the average value for the amount of organic matter that is present at each step and reaches the next level of consumers. Since so little energy is available for the next level of consumers, food chains generally consist of only three or four steps. The loss of energy at each step is so great that very little usable energy remains after four trophic levels.