What type of organisms are producers?

Explain how harmful chemicals enter our body. Write the name given to such a phenomenon.

State one important function of ozone layer in the atmosphere. How is it formed there? Which compounds are responsible for the depletion of ozone layer? How do these compounds enter into the atmosphere?

Which chemical is used in fire extinguishers? How is it harmful?

In a food chain,the third trophic level is always occupied by

State the direction of flow of energy in a food chain. Can food and energy from a trophic level move back to the previous level? Give reasons for your answer.