How do pyramids of net production differ from pyramids of biomass in ecological studies?

True or false: Most of an ecosystem’s net primary productivity is ultimately used for the growth of primary consumers within the ecosystem.

Which of the following is a reason that such a small fraction of the energy that reaches the Earth as solar radiation ends up at the top of the food chain?

Due to biomagnification, there are certain species with a high concentration of heavy metals (e.g., mercury), leading to dietary advisories for vulnerable demographics (e.g., pregnant women and young children) to avoid these species. Given that these advisories are often most critical for species at the top of long marine food chains, which species would this advice most likely apply to?