Life processes are:
(i) Nutrition (ii) Respiration
(iii) Transportation (iv) Excretion.
The life processes need to do:
(i) To provide food that provides energy and material required to sustain life. The process is called nutrition.
(ii) Respiration to supply oxygen to break down food (especially glucose) in the cells of organisms to release energy.
(iii) Transportation process for carrying food and oxygen from one place to another in the body. Also to transport wastes from body cells to excretory tissues.
(iv) Excretion process that removes the by-products produced during other life processes and carried to excretory tissues.
A single-celled organisms does not need specific organs for taking in food, exchange of gases or removal of wastes because the entire surface of the organism is in contact with the environment. Thus tha exchange of gases can take place by simple diffusion and there is no need of special organs.
Why are life processes needed?
Life processes are needed to maintain functions of living organisms like exchange of gases , assimilation of food, circulation of body fluids and removal of waste material