Question

give one for this -accumulation of chemicals at the excessive throphic levels in a food chain

Answer 1

consider the various trophic levels of the ecosystem around you is as given below-
1. primary consumers (herbivores) ex.grasshopper, squirrel, elephant,etc.
2. secondary consumers (carnivores) ex.frog,owl,fox,etc.
3. Apex or top consumers (carnivores) ex. tiger, lion ,etc.
4. Omnivores (mixed consumers) ex.humans, bears,etc.