What in your cells and why are they in your body

Cells are a collection of living structures such as a nucleus, a cell wall and cytoplasm. They are in our body because they make up all of our body and without them we would be nothing.

I think that's right. :)

Cells contain oxygen and other chemicals and nutrients you digested from food. Bone marrow in your body produces it along with white blood cells. You have red blood cells because their purpose is to deliver oxygen and nutrients to all parts of the body. White blood cells are there to defend your body from harmful diseases and are your defense mechanisms. Your cells have 46 chromosomes all together. Chromosomes are the cells blue print. I mean when your cells duplicate, the chromosomes tell the other cell how to duplicate itself. It is like programming a computer to function the same way as another.

Yes, endothermic means it turns cold. and some chemical changes include change of tempature.