15 extra multiple-choice questions for Human Reproduction (12th Standard Zoology, Samacheer Kalvi), beyond the ones printed in the textbook — each with the correct option highlighted and a clear, worked explanation. Free to read in English and Tamil.
Q1
Which extra-embryonic membrane forms the structural base for the umbilical cord and eventually becomes part of the urinary bladder?
- A. Amnion
- B. Yolk sac
- C. AllantoisCorrect
- D. Chorion
Explanation. The allantois serves as the structural base for the umbilical cord and later forms a part of the urinary bladder.
Q2
Which homologous glands in the female reproductive system are located on the anterior wall of the vagina and secrete lubricating fluid, corresponding to the male prostate gland?
- A. Bartholin's glands
- B. Skene's glandsCorrect
- C. Bulbourethral glands
- D. Vestibular glands
Explanation. Skene's glands are situated on the anterior vaginal wall, secrete lubricating fluid, and are homologous to the prostate gland in males.
Q3
During oogenesis, at what stage of follicular development does the fluid-filled cavity called the antrum first appear?
- A. Primary follicle
- B. Secondary follicle
- C. Tertiary follicleCorrect
- D. Graafian follicle
Explanation. The fluid-filled space known as the antrum develops during the transition to a tertiary follicle.
Q4
The descent of the foetus during childbirth causes dilation of the cervix, which initiates a neurohumoral reflex known as the:
- A. Ferguson reflexCorrect
- B. Cushing reflex
- C. Myotatic reflex
- D. Withdrawal reflex
Explanation. Dilation of the cervix and vaginal canal triggers the Ferguson reflex, also called the foetal ejection reflex, which stimulates oxytocin secretion.
Q5
What is the term used to describe the first ejaculation of semen in adolescent males?
- A. Menarche
- B. Orchidectomy
- C. SpermarcheCorrect
- D. Azoospermia
Explanation. Spermarche refers to the first ejaculation of semen, marking the beginning of male reproductive capability at puberty.
Q6
Which of the following hormones is produced exclusively during pregnancy in human females?
- A. Oestrogen
- B. Progesterone
- C. Prolactin
- D. Human chorionic gonadotropin (hCG)Correct
Explanation. Hormones such as hCG, hPL, and relaxin are produced only during pregnancy to support embryonic development.
Q7
Approximately how many hours after fertilization does the dividing embryo form a berry-shaped solid cluster of 16 or more cells called the morula?
- A. 24 hours
- B. 48 hours
- C. 72 hoursCorrect
- D. 96 hours
Explanation. The morula is a loose collection of 16 or more blastomeres that forms about 72 hours after fertilization.
Q8
In a non-pregnant woman, what scar tissue is left behind in the ovary after the complete degeneration of the corpus luteum?
- A. Corpus callosum
- B. Corpus albicansCorrect
- C. Graafian follicle
- D. Secondary oocyte
Explanation. In the absence of fertilization, the corpus luteum degenerates completely and forms a white scar tissue called the corpus albicans.
Q9
The middle piece of the human sperm contains mitochondria spirally twisted around the axial filament. This structure is known as the:
- A. Acrosome
- B. NebenkernCorrect
- C. Centriole
- D. Axoneme
Explanation. The spirally twisted mitochondria around the axial filament in the middle piece of a sperm is called the nebenkern or mitochondrial spiral.
Q10
What is the clinical term used to describe a menstrual cycle that is shorter than 21 days, which may be caused by anterior pituitary hyperactivity?
- A. Amenorrhoea
- B. PolymenorrhoeaCorrect
- C. Oligomenorrhoea
- D. Dysmenorrhoea
Explanation. Polymenorrhoea describes menstrual cycles shorter than 21 days, often associated with frequent ovulation or pituitary hyperactivity.
Q11
The outer thin membranous serous layer of the uterine wall is called the:
- A. Endometrium
- B. Myometrium
- C. PerimetriumCorrect
- D. Epimetrium
Explanation. The wall of the uterus consists of three layers, where the outermost thin serous layer is the perimetrium.
Q12
Which enzyme is present in the acrosome of a human sperm to help it penetrate the outer layers of the ovum during fertilization?
- A. Amylase
- B. Pepsin
- C. HyaluronidaseCorrect
- D. Lipase
Explanation. The acrosome contains hyaluronidase, a proteolytic enzyme (sperm lysin) that assists in penetrating the ovum.
Q13
What term refers to the surgical removal of the testes in males, also known as castration?
- A. OrchidectomyCorrect
- B. Vasectomy
- C. Tubectomy
- D. Prostatitis
Explanation. Orchidectomy is the surgical removal of one or both testes, commonly referred to as castration.
Q14
Which cells in the seminiferous tubules undergo mitotic divisions at puberty and continue to divide throughout a male's life?
- A. Sertoli cells
- B. Interstitial cells
- C. SpermatogoniaCorrect
- D. Leydig cells
Explanation. Spermatogonia, or immature germ cells, multiply by mitosis at puberty and persist throughout the lifespan of the male.
Q15
What is the primary function of the scrotum in human males regarding spermatogenesis?
- A. Hormone secretion
- B. Lubrication
- C. ThermoregulationCorrect
- D. Nutrient storage
Explanation. The scrotum maintains a temperature 2 to 3 degrees Celsius lower than internal body temperature, acting as a thermoregulator.
Frequently asked questions
How many MCQs are there in Human Reproduction?
This chapter has 15 book-back multiple-choice questions, each with the correct answer and a step-by-step explanation.
Are these 12th Standard Zoology MCQs free to practise online?
Yes. Every question, answer and explanation here is free, and you can also take them as a timed practice test.
Where can I find the Human Reproduction book-back answers?
The correct option for each question is highlighted on this page with a worked explanation, plus a quick answer-key summary at the top.
