A father saw his son step down onto the tarmac and watched him as he ran towards him. Describe the changes that occurred in the father's eyes to keep his son's face in focus

b. the carbon cycle ensures living things have a source of hydrogen

Explanation:

the corpus luteum secretes estrogens and progesterone. the latter hormone causes changes in the uterus that make it more suitable for implantation of the fertilized ovum and the nourishment of the embryo. if the egg is not fertilized, the corpus luteum becomes inactive after 10–14 days, and menstruation occurs.

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