Assertion: Progesterone is required for maintenance of the endometrium.
Reason: Endometrium is essential for implantation of embryo.

Dear student,
Please find below the answer:

The correct option is (a).
Progesterone released by the corpus luteum in the first trimester is important for the maintenance of early pregnancy and endometrium (first trimester) till the placenta is formed. In the second and third trimester placenta takes the function of secretion of various hormones including progestogens.  

Hope this clears your doubt.
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