Question

give reason why multicellular organisms require special organ for exchange of gas between their body and their environment?

Answer 1

Multicellular organisms such as humans possess complex body designs. They have specialised cells and tissues for performing various necessary functions of the body such as intake of food and oxygen. Unlike unicellular organisms, multicellular cells are not in direct contact with the outside environment. Therefore, diffusion cannot meet their oxygen requirements.

Whereas in single celled organisms, their whole body is in direct contact with the environment and all the necessary processes like taking in food, excretion etc. take place through their single celled body. they take in food through their single cell and excrete the waste through the same cell. So there is no need of special organs in such organisms. But in complex multicellular organisms, unlike single celled organisms, their whole body is not in direct contact with the environment. Also there are so many cells that the exchange of gases can't be carried out by a single cell and can't meet the energy required . So they have special organs to exchange gases in and out of the body.

Hope this helps!!!

Answer 2

Explanation:

because they do not deffuse gas. they not any pores they are animals cell