This layer is comprised of the nearly invisible layers of gases that surround the planet a. the lithosphere b. the biosphere c. the atmosphere d. the hydrosphere

c

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.