I believe the answer is Capillaries
The answer is A irrelevant.
The correct answer is option C
All the animals are Heterotrophs as they cannot perform photosynthesis.
Except some of the sponges, all the animals are heterotrophs as they cannot make their own food(photosynthesis).
Heterotrophs depends on autotrophs or some other organisms for their food.
They are dependent on other organisms for their energy needs.
Not a lot besides the fact that they are both mixtures in water, because a solution is a mixture in which the solutes ( solids) dissolve, and suspension is a mixture in which the solutes don't dissolve.