Menstrual cycle

Correct answer: A. अंडाशय से परिपक्व अंडाणु का मुक्त होना

Explanation: Ovulation is the release of a mature secondary oocyte from an ovarian follicle, usually around the middle of a typical menstrual cycle. The oocyte can then enter the oviduct, where fertilisation may occur. Sperm production is spermatogenesis, attachment to the uterine lining is implantation, and milk production or secretion is lactation; therefore option A is correct.

Correct answer: B. 28 days

Explanation: The standard school-level average for the human menstrual cycle is about 28 days. The cycle is counted from the first day of menstrual bleeding to the first day of the next menstrual period, and it includes menstrual, follicular, ovulatory, and luteal events. Individual cycles may be shorter or longer, but 28 days is the accepted approximate average; therefore B is correct.

Correct answer: A. Menstrual phase

Explanation: In the standard classification, day 1 of the menstrual cycle is the first day of menstrual bleeding, so the cycle begins with the menstrual phase. The follicular phase overlaps partly with this period and continues afterward, but ovulation occurs later after the mid-cycle hormonal surge. The luteal phase follows ovulation; thus the menstrual phase, option A, is the correct answer.