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.
The answer is; E
With environmental changes, the carrying capacity can either increase or decrease. It is important to note that the carrying capacity is the number of individuals of a species that a habitat can sustain indefinitely. With favorable environmental conditions, the carrying capacity increases while unfavorable environmental conditions decrease the carrying capacity.
None of the above? I’m guessing, secondary, primary and tertiary doesn’t sound right !