"Energy flow in a food chain is unidirectional." Justify this statement. Explain how the pesticides enter a food chain and subsequently get into our body.

(N/A) The flow of energy in a food chain is unidirectional because energy captured by autotrophs (producers) from the sun is passed to successive trophic levels and is never returned to the previous level or the sun.
As energy moves through trophic levels, a significant portion is lost as heat at each step, making it unavailable for the previous level.
Pesticides are non-biodegradable chemicals used to protect crops. When these chemicals are washed into the soil or water bodies, they are absorbed by plants along with water and minerals.
Since these chemicals cannot be broken down by biological processes, they accumulate at each trophic level in a process called biological magnification. As humans are often at the top of the food chain, these pesticides eventually enter and accumulate in our bodies.