Question

Why is there less biomass at the top of the energy pyramid?
Secondary and tertiary consumers live longer, so there are fewer of them because they reproduce more slowly.
Secondary and tertiary consumers have to consume a lot more food to support themselves, so there are fewer of them.
Secondary and tertiary consumers are larger, so there are fewer of them.
Secondary and tertiary consumers have bigger ranges, so there are fewer of them because they each need a lot of space.

Answer 1

Best answer: "Secondary and tertiary consumers have to consume a lot more food to support themselves, so there are fewer of them."

Explanation: energy transfer between trophic levels is inefficient (only a small fraction — roughly 10% — of the energy at one level becomes available to the next). That means higher levels can support far less biomass, so there are fewer predators. Larger body size and slower reproduction (options 3 and partly 1) can contribute in some systems, and predators often need larger ranges (option 4) too, but the primary reason is the loss of energy at each transfer.