Which of the following occurs earliest in the menstrual cycle?
(2) The ovaries release a mature egg into the fallopian tubes
(2) Progesterone levels rise, thickening the uterine lining
() The uterine lining breaks down and is shed through the vagina
(0) Estrogen levels rise, thickening the uterine lining

an adaptation is a change or process by which an organism takes to be better suited for its environment. for example; migration is a behavioral adaptation, this is needed because birds are not built to last extremely cold climates. there are different adaptations because there are different species needing to adjust to different things, bears don't migrate; they hibernate.

a symbiotic relationship with the mitochondria