Given below are statements: one is labelled as assertion (A) and the other is labelled as Reason (R).

Assertion (A): Endometrium is necessary for the implantation of blastocyst.

Reason (R) : In the absence of fertilisation, the corpus luteum degenerates leading to disintegration of endometrium.

In the light of the above statements choose the correct answer from the options given below.

Assertion is true. The corpus luteum secretes large amounts of progesterone, which is essential for maintenance of the endometrium. Endometrium is necessary for implantation of the fertilised ovum and other events of pregnancy.

Reason is true. In the absence of fertilisation, the corpus luteum degenerates. This causes disintegration of the endometrium, leading to menstruation, marking a new cycle.

Hence, Assertion and reason are true but reason is not the correct explanation of assertion.