Q30. Which tube serves as the common outlet for urine and semen in human males?
[RRB Technician Grade III — 30 December 2024]
(A) Urethra
(B) Urinary bladder
(C) Scrotum
(D) Vas deferens
Answer: (A) Urethra
Explanation: The male urethra carries urine from the bladder and semen during ejaculation, although these functions are regulated separately. The vas deferens carries sperm toward the ejaculatory duct. The bladder stores urine, and the scrotum contains the testes.
Q29. Through which organ are oxygen and nutrients transferred to a growing fetus?
[RRB Technician Grade III — 28 December 2024]
(A) Scrotum
(B) Placenta
(C) Oviduct
(D) Ovary
Answer: (B) Placenta
Explanation: The placenta is the exchange organ joining maternal supply with fetal needs. Nutrients and oxygen cross its barrier into fetal circulation, while carbon dioxide and wastes move in the opposite direction. It also produces hormones important for sustaining pregnancy.
Q28. Why are human testes located in the scrotum outside the abdominal cavity?
[RRB Technician Grade III — 28 December 2024]
(A) To keep them much hotter than the body
(B) To maintain a temperature below core body temperature
(C) To ensure they remain at exactly core temperature
(D) To store urine temporarily
Answer: (B) To maintain a temperature below core body temperature
Explanation: Sperm production functions optimally at a temperature roughly 2–2.5°C below core body temperature. The scrotum, with muscular and vascular temperature-regulating mechanisms, helps maintain this cooler environment. Excessive sustained heat may impair normal spermatogenesis.
Q27. Which structure transports the ovulated oocyte toward the uterus?
[RRB Technician Grade III — 24 December 2024]
(A) Fallopian tube
(B) Vagina
(C) Cervix
(D) Placenta
Answer: (A) Fallopian tube
Explanation: Fimbriae near the infundibulum help collect the released secondary oocyte. Ciliary movement and muscular contractions move it through the oviduct toward the uterus. Fertilisation usually occurs in the ampullary–isthmic region of the fallopian tube.
Q26. Which human reproductive cell is motile by means of a flagellum?
[RRB Junior Engineer, Stage I — 16 December 2024]
(A) Embryo
(B) Ovum
(C) Spermatozoon
(D) Zygote
Answer: (C) Spermatozoon
Explanation: A mature spermatozoon possesses a flagellar tail whose movement provides propulsion through fluid. Mitochondria in its middle piece supply energy. The human secondary oocyte is not independently motile, and neither the zygote nor the embryo is a flagellated gamete.
Q25. Which combination chiefly generates genetic variation during sexual reproduction?
[UPSC NDA — 3 September 2023]
(A) Mitosis and budding
(B) Meiosis and fertilisation
(C) Binary fission and mitosis
(D) Vegetative propagation and fragmentation
Answer: (B) Meiosis and fertilisation
Explanation: During meiosis, crossing over and independent assortment create genetically varied haploid gametes. Random fertilisation then combines genetic information from two parents in new ways. Mitosis and asexual reproductive processes generally preserve parental genetic combinations more closely.
Q24. Which kind of cell division is called reduction division?
[SSC CHSL Tier I — 8 August 2023]
(A) Telophase
(B) Meiosis
(C) Prophase
(D) Mitosis
Answer: (B) Meiosis
Explanation: Meiosis I reduces chromosome number from diploid to haploid by separating homologous chromosome pairs. This allows fertilisation to restore diploidy without doubling the chromosome count every generation. Mitosis maintains chromosome number, while prophase and telophase are division stages.
Q23. What does IVF stand for in reproductive biology?
[SSC MTS, 2022 Cycle (exam held 2 May 2023)]
(A) In vitro fragmentation
(B) In vitro fertilisation
(C) Internal vascular fusion
(D) In vivo fission
Answer: (B) In vitro fertilisation
Explanation: In vitro fertilisation involves bringing sperm and oocytes together under laboratory conditions. Following fertilisation and early embryo culture, an embryo can be transferred to the uterus. It is an assisted reproductive technique and differs from normal internal fertilisation.
Q22. What process occurs when the endometrium breaks down in the absence of pregnancy?
[RRB Group D — 29 September 2022]
(A) Menopause
(B) Menstruation
(C) Spermiation
(D) Implantation
Answer: (B) Menstruation
Explanation: When fertilisation and implantation do not occur, the corpus luteum degenerates and progesterone and oestrogen levels fall. This causes the functional uterine lining to disintegrate, producing menstrual flow. Menopause, by contrast, represents permanent cessation of ovarian cycles.
Q21. In which part of the female reproductive tract does human fertilisation normally occur?
[RRB Group D — 28 September 2022]
(A) Vagina
(B) Uterine cavity
(C) Cervix
(D) Ampullary–isthmic region of the oviduct
Answer: (D) Ampullary–isthmic region of the oviduct
Explanation: Human sperm generally meet the secondary oocyte in the ampullary–isthmic region of the fallopian tube. Fusion initiates development of a diploid zygote, which undergoes cleavage during passage toward the uterus. Implantation subsequently takes place in the endometrium.
