Food chains are sometimes short because a. only a single species of herbivore feeds on each plant species. b. local extinction of a species causes extinction of the other species in its food chain. c. most of the energy in a trophic level is lost as energy passes to the next higher level. d. most producers are inedible.

Verified step by step guidance

1. Identify the key concept: The question is asking why food chains are sometimes short, which relates to the efficiency of energy transfer across different trophic levels in an ecosystem.
2. Analyze the options: Consider how each option relates to the length of food chains and the efficiency of energy transfer.
3. Evaluate option c: This option states that most of the energy in a trophic level is lost as energy passes to the next higher level. Recall that according to the 10% rule in ecology, only about 10% of the energy is transferred from one trophic level to the next, with the rest lost primarily as heat.
4. Compare with other options: Options a, b, and d do not directly address the general principle of energy transfer efficiency in ecosystems, which is a fundamental reason for the shortness of many food chains.
5. Conclude that the correct answer is c: Since energy loss at each trophic level restricts the length of sustainable food chains, option c is the most accurate explanation for why food chains are sometimes short.