Where does carbon come from? what is made of carbon?

Carbon is also found in the atmosphere where it's a part of carbon dioxide gas emitted when fossil fuels are burned and when living organisms breathe. It's in organic matter in the soil, and it's in rocks. But far and away the most carbon on Earth is stored in a surprising place: the ocean.

Explanation:

the menstrual cycle – higher tier. negative feedback mechanisms affect the production of hormones in the menstrual cycle. oestrogen also stimulates the release of lh (luteinising hormone) from the pituitary gland, which in turn controls the production of progesterone.