(i) Presence of membrane bound organelles, including a nucleus. This helps the organism organise specialised functions.

Organisms without demarcated organelles will have biochemical pathway organised in different ways, which would further have an effect on every aspect of cell design.

(ii) Whether cells occur singly, or grouped together or do they live as an Indivisible group

Cells which are grouped together to form a single organism use the principle of division of labour. In such an animal, all cells would not be identical, but a group of cells will carry out specialized function.

(iii) Does the organism produce own food through photosynthesis

(iv) The level of organization of body of organisms who perform photosynthesis

(v) Of the animals, how does the individual's body develop and organizers different parts, and what are the specialized organs found for different functions.