Read the following statements concerning the corpus luteum:
(I) It is formed during the follicular phase of the menstrual cycle. (II) It secretes large amounts of progesterone, which is essential for endometrial maintenance. (III) If fertilization fails to occur, the corpus luteum degenerates. (IV) Its degeneration causes progesterone levels to rise, triggering menstruation.
Explanation: Statement (I) is incorrect because the corpus luteum is formed during the luteal (secretory) phase, not the follicular phase. Statements (II) and (III) are correct. Statement (IV) is incorrect because degeneration of the corpus luteum causes progesterone levels to fall, leading to menstruation.
Question 42 of 100
📘 CLASS XII
Which of the following statements regarding spermatogonia are correct?
(I) Spermatogonia are immature male germ cells present on the inside wall of seminiferous tubules. (II) They multiply by meiotic division to decrease chromosome number before puberty. (III) Each spermatogonium is diploid and contains 46 chromosomes. (IV) Some spermatogonia periodically undergo meiosis as primary spermatocytes.
Explanation: Statements (I), (III), and (IV) are correct. Statement (II) is incorrect because spermatogonia multiply by mitotic division, not meiotic division.
Question 43 of 100
📘 CLASS XII
Examine the statements regarding female accessory reproductive ducts:
(I) Oviducts, uterus, and vagina constitute the female accessory ducts. (II) Each fallopian tube is about 10–12 cm long and extends from the periphery of each ovary to the uterus. (III) The uterus is a paired structure supported by pelvic ligaments. (IV) The cavity of the cervix is called the cervical canal, which along with the vagina forms the birth canal.
Explanation: Statements (I), (II), and (IV) are correct. Statement (III) is incorrect because the uterus is a single organ, also known as the womb.
Question 44 of 100
📘 CLASS XII
Read the statements below concerning hormonal regulation at puberty in males:
(I) Hypothalamic GnRH secretion increases significantly at puberty. (II) High GnRH levels act on the posterior pituitary gland to stimulate gonadotropins. (III) LH acts on Leydig cells to stimulate androgen synthesis. (IV) FSH acts on Sertoli cells to stimulate factors helping in spermiogenesis.
Explanation: Statements (I), (III), and (IV) are correct. Statement (II) is incorrect because GnRH acts on the anterior pituitary gland, not the posterior pituitary.
Question 45 of 100
📘 CLASS XII
Regarding the sex determination of a human baby, evaluate these statements:
(I) The sex of the baby is determined scientifically by the genetic contribution of the mother. (II) All haploid ova produced by the female contain only the X chromosome. (III) 50% of male gametes carry the X chromosome, while the other 50% carry the Y chromosome. (IV) Zygotes carrying XX develop into a female, while XY develop into a male baby.
Explanation: Statement (I) is incorrect because the sex of the baby is determined by the father (male gamete), as males produce both X- and Y-bearing sperms. Statements (II), (III), and (IV) are correct.
Question 46 of 100
📘 CLASS XII
Analyze the structure of the human ovary and its ligaments:
(I) Each ovary is about 2 to 4 cm in length. (II) It is connected to the pelvic wall and uterus by ligaments. (III) The ovary is covered by a thick epithelium enclosing the ovarian stroma. (IV) The ovarian stroma is divided into a peripheral cortex and an inner medulla.
Explanation: Statements (I), (II), and (IV) are correct. Statement (III) is incorrect because the ovary is covered by a thin epithelium, not a thick one.
Question 47 of 100
📘 CLASS XII
Identify the correct statements concerning human embryonic cleavage:
(I) Cleavage begins as the zygote moves through the isthmus toward the uterus. (II) Blastomeres are daughter cells formed by unequal meiotic divisions of the zygote. (III) An embryo with 8 to 16 blastomeres is called a morula. (IV) The blastocyst stage follows the morula stage during movement into the uterus.
Explanation: Statements (I), (III), and (IV) are correct. Statement (II) is incorrect because blastomeres are produced by rapid mitotic (cleavage) divisions, not meiotic divisions.
Question 48 of 100
📘 CLASS XII
Read the statements below regarding uterine wall tissues:
(I) Perimetrium is the middle thick muscular layer. (II) Myometrium is the outer thin membranous layer. (III) Endometrium is the inner glandular layer lining the uterine cavity. (IV) The endometrium undergoes cyclical changes during the menstrual cycle.
Explanation: Statements (III) and (IV) are correct. Statements (I) and (II) are incorrect because the perimetrium is the outer thin membranous layer, while the myometrium is the middle thick muscular layer.
Question 49 of 100
📘 CLASS XII
Select the correct statements regarding the primary male sex hormone:
(I) Androgens are synthesized and secreted by Leydig cells. (II) These hormones are essential for maintaining the function of male accessory ducts and glands. (III) Androgens play no role in the process of spermatogenesis. (IV) Their synthesis is directly stimulated by the pituitary follicle stimulating hormone (FSH).
Explanation: Statements (I) and (II) are correct. Statement (III) is incorrect because androgens stimulate spermatogenesis. Statement (IV) is incorrect because androgen secretion is stimulated by Luteinizing Hormone (LH), not FSH.
Question 50 of 100
📘 CLASS XII
Review the statements concerning the female external genitalia:
(I) Mons pubis is a cushion of fatty tissue covered by skin and pubic hair. (II) The labia majora extend down from the mons pubis and surround the vaginal opening. (III) The labia minora are fleshy, paired folds of tissue located above the labia majora. (IV) The clitoris lies at the lower junction of the two labia majora below the urethral opening.
Explanation: Statements (I) and (II) are correct. Statement (III) is incorrect because the labia minora are paired folds of tissue beneath the labia majora. Statement (IV) is incorrect because the clitoris lies at the upper junction of the two labia minora, above the urethral opening.
