Question

In single celled organisms diffusion is sufficient to meet all their requirement of food exchange of gases or removal of waste but it is not in the case of multi - cellular organisms. Explain the reasons for these difference.

Answer 1

In single celled organisms,the entire surface of the organism is in contact with the environment but in multi cellular organisms all the cells may not be in direct contact with the surrounding environment thus simple diffusion will not meet the requirement of all the cells