Reason (R): These organs are responsible for the production,
maturation, transport, and delivery of sperm.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The male reproductive organs are involved in
producing sperm, maturing them, and transporting them for fertilization.
Reason (R): Spermatogenesis requires a temperature that is
2-3°C lower than the normal body temperature.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The testes are outside the body to maintain the
lower temperature required for sperm production.
Reason (R): These organs work together for the production,
transportation, and fertilization of the female gamete, and for the development
of the fetus.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The female reproductive system supports egg
production, fertilization, and fetal development.
Reason (R): Oogenesis begins before birth, continues until
menopause, and involves the formation of ova.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Oogenesis begins during fetal development and
continues in cycles throughout the reproductive years.
Reason (R): The four phases are menstrual, follicular,
ovulation, and luteal phases, which coordinate the preparation of the female
body for pregnancy.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: These phases regulate the release of hormones and
the maturation of the egg for fertilization.
Reason (R): Ovulation is triggered by the peak levels of
luteinizing hormone (LH) and follicle-stimulating hormone (FSH).
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: A surge in LH and FSH triggers ovulation, where
the mature egg is released from the ovary.
Reason (R): The sperm meets the egg in the fallopian tube,
where fertilization occurs to form a zygote.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Fertilization happens in the fallopian tube, where
the sperm and egg fuse to form a zygote.
Reason (R): The blastocyst then implants in the uterine wall
for further development into an embryo.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The blastocyst, formed from rapid cell division,
implants in the uterine wall for further fetal development.
Reason (R): The placenta is formed from both maternal and fetal
tissues and allows for bidirectional exchange of substances.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The placenta allows for the exchange of nutrients,
gases, and wastes between the mother and fetus.
Reason (R): Pregnancy is divided into three trimesters, each
lasting approximately 3 months, during which different fetal developments occur.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The three trimesters represent different stages of
fetal growth and maternal changes during pregnancy.
Reason (R): Prolactin is secreted by the pituitary gland after
childbirth to stimulate milk production.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: After childbirth, prolactin stimulates the mammary
glands to produce milk.
Reason (R): The testes are responsible for continuous sperm
production throughout the male's life.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The testes continuously produce sperm, which are
stored and matured in the epididymis.
Reason (R): Sperm undergo maturation in the epididymis,
acquiring the ability to move and fertilize the egg.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Sperm mature in the epididymis, gaining motility
and the ability to fertilize an egg.
Reason (R): The acrosomal enzymes help the sperm penetrate the
egg's protective layers during fertilization.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The acrosome releases enzymes that help the sperm
penetrate the egg during fertilization.
Reason (R): Progesterone maintains the endometrial lining to
support pregnancy until the placenta takes over hormone production.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The corpus luteum secretes progesterone, which
supports the endometrium during early pregnancy.
Reason (R): Estrogen promotes the growth and maturation of the
ovarian follicle.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Estrogen is essential for the growth and
maturation of the ovarian follicle during the follicular phase.
Reason (R): The release of the egg is triggered by the
luteinizing hormone (LH) surge.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: A surge in LH triggers ovulation, which releases a
mature egg from the ovary.
Reason (R): The menstrual cycle involves cyclic changes in
estrogen, progesterone, LH, and FSH levels.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Hormonal fluctuations regulate the stages of the
menstrual cycle.
Reason (R): IVF involves fertilizing the egg outside the
woman's body and then implanting the zygote into the uterus.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: IVF assists in fertility treatment by combining
the egg and sperm outside the body, followed by implantation.
Reason (R): Prolactin stimulates milk production, while
oxytocin is responsible for milk ejection during breastfeeding.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Prolactin and oxytocin regulate milk production
and ejection during lactation.
Reason (R): Menopause marks the cessation of menstrual cycles
due to the decrease in ovarian hormone production.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Menopause occurs when ovarian hormone levels
decline, halting the menstrual cycle and fertility.
Reason (R): The uterus provides an environment with nutrients
and protection for the developing fetus.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The uterus provides the necessary environment for
fetal growth, development, and nourishment.
Reason (R): Testosterone is responsible for the development of
male secondary sexual characteristics.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Testosterone, produced by the testes, stimulates
the development of male characteristics like facial hair and deep voice.
Reason (R): The vas deferens is part of the male reproductive
tract and acts as a conduit for sperm during ejaculation.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The vas deferens transports mature sperm from the
epididymis to the urethra for ejaculation.
Reason (R): Fertilization occurs inside the female's body when
sperm meets the egg in the fallopian tube.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Human fertilization occurs inside the female
reproductive tract, specifically in the fallopian tube.
Reason (R): The seminiferous tubules contain Sertoli cells that
provide nourishment to the developing sperm.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Sertoli cells in the seminiferous tubules support
and nourish developing sperm cells, facilitating spermatogenesis.
Reason (R): Progesterone helps in the maintenance of the
endometrium for possible implantation of a fertilized egg.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Progesterone secreted by the corpus luteum
thickens the endometrial lining, providing an optimal environment for
implantation.
Reason (R): The zygote undergoes cleavage divisions to form a
blastocyst.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: After fertilization, the egg becomes a zygote,
which divides to form a blastocyst that can implant in the uterus.
Reason (R): The cervix dilates during labor to allow the baby
to pass through the birth canal.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The cervix expands during childbirth to allow the
passage of the baby from the uterus into the vagina.
Reason (R): The testes are located outside the abdominal cavity
in the scrotum for temperature regulation.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The testes are located outside the body in the
scrotum to maintain a cooler temperature necessary for sperm production.
Reason (R): LH and FSH regulate the reproductive processes in
both males and females.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: LH and FSH are essential in controlling the
release of hormones like estrogen and testosterone and regulating gametogenesis.
Reason (R): The vagina also serves as the organ for the passage
of menstrual fluid from the body.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The vagina functions as a birth canal during
childbirth and also facilitates the exit of menstrual fluid.
Reason (R): The sperm matures in the epididymis, gaining
motility and the ability to fertilize an egg.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The epididymis is responsible for storing and
maturing sperm, allowing them to acquire motility.
Reason (R): The uterus provides an environment with a suitable
temperature and nourishment for embryo development.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The uterus is adapted for fetal development,
offering protection and the necessary conditions for growth.
Reason (R): A drop in progesterone levels causes the breakdown
of the endometrial lining, leading to menstrual bleeding.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: If fertilization does not occur, progesterone
levels fall, leading to the shedding of the endometrial lining (menstruation).
Reason (R): The first trimester is crucial for organogenesis,
the process where the organs of the embryo start developing.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The first trimester is critical for the formation
of organs and tissues, marking significant developmental milestones.
Reason (R): These enzymes help the sperm penetrate the zona
pellucida of the egg during fertilization.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The acrosome contains enzymes that assist in
breaking down the egg's protective layers during fertilization.
Reason (R): Only a few sperm reach the egg, and only one
fertilizes it.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Millions of sperm are produced to increase the
chances of successful fertilization, but only one sperm fertilizes the egg.
Reason (R): The hormones estrogen and progesterone control the
ovarian cycle and the release of eggs during ovulation.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Estrogen and progesterone regulate the release of
eggs through their effects on the ovaries and menstrual cycle.
Reason (R): The fusion of male and female gametes restores the
diploid number of chromosomes in the zygote.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The sperm and egg fuse during fertilization to
form a zygote, which has the complete set of chromosomes.
Reason (R): The placenta forms from both maternal and fetal
tissues, providing a direct connection between the mother and fetus.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The placenta allows the exchange of substances
between the mother and fetus, supporting fetal growth.
Reason (R): The hormones secreted by the placenta include human
chorionic gonadotropin (hCG) and progesterone, which help maintain pregnancy.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: hCG and progesterone are secreted by the placenta
to maintain pregnancy by supporting the endometrial lining and preventing
ovulation.
Reason (R): IVF involves combining the egg and sperm outside
the body and implanting the resulting embryo into the uterus.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: IVF assists individuals with infertility by
enabling fertilization outside the body and facilitating implantation.
Reason (R): Estrogen and progesterone provide negative and
positive feedback to regulate the secretion of FSH and LH.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Estrogen and progesterone regulate FSH and LH
through feedback mechanisms to maintain the menstrual cycle.
Reason (R): The zygote divides by mitosis to form a blastocyst,
which then implants in the uterine wall.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The fertilized egg divides to form a blastocyst,
which then implants in the uterus to establish pregnancy.
Reason (R): Prolactin and oxytocin are hormones involved in
milk production and ejection.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Prolactin stimulates milk production, while
oxytocin triggers the ejection of milk from the mammary glands.
Reason (R): Gametes have half the number of chromosomes,
ensuring the zygote has a complete set of chromosomes.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Gametes (sperm and egg) are haploid to restore the
diploid number when they fuse during fertilization.
Reason (R): Menopause is characterized by the cessation of
menstrual cycles and a drop in estrogen and progesterone levels.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Menopause marks the end of reproductive years due
to a decline in ovarian function and hormone production.
Reason (R): The mother has two X chromosomes and passes one of
them to her offspring.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Males inherit an X chromosome from their mother
and a Y chromosome from their father, determining their male sex.
Reason (R): The interstitial cells in the testes secrete
testosterone, which is crucial for sperm development.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Testosterone, produced by the interstitial cells
in the testes, stimulates sperm production and the development of male secondary
sexual characteristics.