What are some nutrients necessary to sustain life that are cycled within a biosphere?

Which of the following are the functions of the skeletal system? blood cell production in soft marrow tissues and mineral reserves largest organ of the body for defense and support vitamin d production and pumping blood through vessels voluntary movement and contractile movement

Surrounded by microtubules, located near the nucleus. (don't try to google it) (give answer only if u know)

What are the characteristics of living things