Explain why man is at top of the food chain?

Humans aren't at the top of the food chain. In fact, we're nowhere near the top. Ecologists rank species by their diets using a metric called the trophic level. 

Because men are consumers. At the bottom are plants which has the most energy level, bugs eat plants about 20% energy is lost, birdseat the bugs that ate the plant which lost about 40% energy, and the tigers and bears eat the bug eaters who ate the plant = 80% energy lost and then we eat the bigger animals so we consume less energy. We eat everything