Q40. Which organ sheds its inner lining during menstruation?
[RRB Technician Grade III — 9 October 2026]
(A) Fallopian tube
(B) Uterus
(C) Liver
(D) Ovary
Answer: (B) Uterus
Explanation: Menstrual bleeding occurs when the functional layer of the uterine endometrium breaks down and is expelled. Falling ovarian hormone levels trigger this process if implantation has not occurred. The ovaries regulate the cycle, but the lining being shed belongs to the uterus.
Q39. Which event is counted as Day 1 of the human menstrual cycle?
[RRB Technician Grade III — 8 October 2026, Shift 2]
(A) Beginning of menstrual bleeding
(B) Release of the secondary oocyte
(C) Union of sperm and ovum
(D) Embedding of the blastocyst
Answer: (A) Beginning of menstrual bleeding
Explanation: The menstrual cycle is conventionally counted from the first day of menstrual flow. At this time, the uterine lining is being shed. Ovulation generally occurs later during the cycle; fertilisation and implantation occur only when conception takes place.
Q38. What is the commonly cited average duration of a human menstrual cycle?
[RRB Technician Grade III — 8 October 2026, Shift 1]
(A) 60 days
(B) 7 days
(C) 14 days
(D) 28 days
Answer: (D) 28 days
Explanation: NCERT uses approximately 28 or 29 days as the typical menstrual cycle length. Actual cycles vary among individuals and can fluctuate over time. The duration is measured from the start of one menstrual period to the start of the next.
Q37. From where does a developing embryo of a placental mammal principally obtain nourishment?
[RRB Technician Grade III — 8 October 2026, Shift 1]
(A) Eggshell
(B) Maternal body
(C) Surrounding pond water
(D) An external yolk sac alone
Answer: (B) Maternal body
Explanation: In placental mammals, nutrients and oxygen reach the developing conceptus from maternal circulation through the placenta. Maternal and fetal blood generally remain separated by placental tissue. This arrangement supports sustained embryonic and fetal growth within the uterus.
Q36. Why is feeding colostrum to a newborn especially beneficial?
[RRB Technician Grade III — 6 October 2026, Shift 3]
(A) It changes the newborn’s blood group
(B) It guarantees early tooth eruption
(C) It replaces all vaccinations
(D) It supplies antibodies and nutrients
Answer: (D) It supplies antibodies and nutrients
Explanation: Colostrum is the first milk produced around childbirth. It is rich in protective immunoglobulins, especially secretory IgA, and provides concentrated nutrients. Early breastfeeding helps protect the infant against infection while feeding and bonding are established after delivery.
Q35. In spermatogenesis, which cell undergoes the first meiotic division?
[UPSC NDA — 12 April 2026]
(A) Spermatogonium
(B) Primary spermatocyte
(C) Secondary spermatocyte
(D) Sertoli cell
Answer: (B) Primary spermatocyte
Explanation: A diploid primary spermatocyte enters meiosis I and produces two haploid secondary spermatocytes. Each secondary spermatocyte then undergoes meiosis II, forming spermatids. Spermatogonia multiply mitotically, while Sertoli cells support the differentiating germ cells inside seminiferous tubules.
Q34. Which structure is absent from the normal male reproductive system?
[UPSC CDS II (General Knowledge) — 14 September 2025]
(A) Prostate gland
(B) Testis
(C) Cervix
(D) Scrotum
Answer: (C) Cervix
Explanation: The cervix is the narrow lower part of the uterus that opens into the vagina and belongs to female reproductive anatomy. The testes produce sperm, the scrotum houses the testes, and the prostate contributes secretions to semen.
Q33. Which pair consists entirely of structures of the male reproductive system?
[RRB NTPC Graduate Level, Stage II — 13 October 2025]
(A) Vas deferens and oviduct
(B) Uterus and vagina
(C) Oviduct and penis
(D) Vas deferens and scrotum
Answer: (D) Vas deferens and scrotum
Explanation: The vas deferens transports sperm from the epididymis toward the ejaculatory duct, while the scrotum contains the testes. An oviduct, uterus and vagina belong to the female reproductive tract. Therefore, only the final pair contains two male structures.
Q32. The uterus communicates with the vagina through which structure?
[RRB Paramedical — 28 April 2025]
(A) Oviduct
(B) Vas deferens
(C) Ovary
(D) Cervix
Answer: (D) Cervix
Explanation: The cervix is the lower cylindrical part of the uterus. Its cervical canal connects the uterine cavity with the vagina, allowing menstrual flow outward and sperm passage inward. During childbirth, the cervix dilates to permit delivery of the baby.
Q31. What is the biological term for the first menstrual period?
[NEET UG — 2025]
(A) Menopause
(B) Menarche
(C) Ovulation
(D) Implantation
Answer: (B) Menarche
Explanation: Menarche marks the first menstrual bleeding and generally occurs during puberty as ovarian and uterine cycles mature. Menopause denotes the permanent cessation of menstrual cycles later in life. Ovulation means oocyte release, whereas implantation occurs after fertilisation.