Question

What is the main function of the circulatory system in multicelluar organisms?

Answer 1

Multicellular organisms do not have direct access to their nutrients for all their cells, so the circulatory system brings it to them via blood, which can then diffuse into the cells that need it.

Answer 2

Yes, it provides oxygen and nutrients to the cells. True.

Answer 3

I forgot to add that it picks up the waste that is collecting for excretion. That may not apply to all multicellular organisms.