Menstrual flow occurs due to lack of :
- Progesterone
- FSH
- Oxytocin
- Vasopressin
Answer
(1) Progesterone
Solution
As per NCERT, in the absence of fertilisation the corpus luteum degenerates.
⇒ This causes a fall in progesterone, which is needed to maintain the endometrium.
⇒ The endometrium then disintegrates, leading to menstruation (a new cycle).
∴ Menstrual flow occurs due to lack of progesterone.
Answer: (1)