The water vascular system of a sea star enables movement, digestion and respiration through the use of water to exert force on limbs known as tube feet. The vascular system is primarily water but also contains coelomocytes, protein and potassium salts.
Answer:
to understand the human and animal behaviour
Explanation:
By looking at the biological bases of human behavior, psychologists are better able to understand how the brain and physiological processes might influence the way people think, act, and feel.
generate energy by photosynthesis
The answer is A. - Prokatyotic cells lack a defined nucleus while eukaryotic cells do have one :) I loved learning about the cells in biology! But I noticed your question is worded a little differently so the nucleus would be the one thing a eukaryotic cell has that a prokatyotic cell does not...