Differentiate between food chain and food web.

We do not clean ponds or lakes, but an aquarium needs to be cleaned. Why?

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

Why is the damage to the ozone layer a cause for concern? What steps are being taken to limit this damage?

What are the functions of an ecosystem?