Discuss efficiency of skin as a barrier

The skin prevents pathogens from entering our body. It covers almost all parts of our bodies and if we get a cut, the skin will begin to heal itself so no bacteria can get into our bodies and cause infections.

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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