What are lymph nodes and where are they found?

lymph flows through the lymph nodes. Lymph nodes themselves are each of a number of small swellings in the lymphatic system where lymph is filtered and lymphocytes are formed. They can be found at the neck, underarms, chest, abdomen, and groin

Explanation:

the answer to your question is sperm

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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