A is made of a sugar, a nitrogen base , and a phosphate group.

maritime tropical may be your answer.

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.

it is a limiting nutrient limited by a single nutrient in the ecosystem, & the single goes very slow.