1. Which combination correctly describes human reproduction?
ⓐ. Asexual, external fertilisation, oviparous
ⓑ. Sexual, external fertilisation, viviparous
ⓒ. Sexual, internal fertilisation, viviparous
ⓓ. Asexual, internal fertilisation, oviparous
Correct Answer: Sexual, internal fertilisation, viviparous
Explanation: Human reproduction involves the fusion of male and female gametes, so it is sexual reproduction. Fertilisation normally takes place inside the female body, which makes it internal fertilisation. The offspring develops within the mother and is born alive, so humans are viviparous. These three features together define the general reproductive pattern in humans.
2. Which feature best shows that humans are viviparous?
ⓐ. Gametes are formed by meiosis
ⓑ. The embryo develops inside the female body and the offspring is born alive
ⓒ. Fertilisation occurs outside the body in a moist medium
ⓓ. A zygote is formed without fusion of gametes
Correct Answer: The embryo develops inside the female body and the offspring is born alive
Explanation: Viviparity refers to a mode of reproduction in which the developing young remains inside the mother for development. In humans, the embryo and foetus grow within the uterus before birth. This differs from oviparity, where development occurs in an egg laid outside the body. Live birth is therefore a key sign of viviparous reproduction.
3. In humans, internal fertilisation means that
ⓐ. the zygote is formed in the external environment
ⓑ. the sperm is produced outside the body
ⓒ. the ovum is formed after birth
ⓓ. the male and female gametes fuse inside the female reproductive tract
Correct Answer: the male and female gametes fuse inside the female reproductive tract
Explanation: Internal fertilisation means that the actual union of sperm and ovum takes place within the female body. In humans, sperm is deposited in the female tract and fertilisation usually occurs within the oviduct. This protects the gametes and the early zygote from direct exposure to the external environment. It is one of the major reproductive features of mammals.
4. What is the primary biological significance of reproduction in humans?
ⓐ. It increases the body temperature of the parents
ⓑ. It ensures continuity of the species
ⓒ. It prevents all genetic variation
ⓓ. It replaces the need for growth and development
Correct Answer: It ensures continuity of the species
Explanation: Reproduction is essential because it produces new individuals of the same species. Without reproduction, a species would eventually disappear as older individuals die. In humans, reproduction transfers hereditary information from one generation to the next. That is why reproduction is central to the continuity of life.
5. Which statement about sexes in humans is correct?
ⓐ. Humans are unisexual, with male and female reproductive roles present in separate individuals
ⓑ. Humans are hermaphrodite, with both reproductive systems functional in the same individual
ⓒ. Humans change sex naturally during every reproductive cycle
ⓓ. Humans reproduce without formation of specialized sex cells
Correct Answer: Humans are unisexual, with male and female reproductive roles present in separate individuals
Explanation: In humans, male and female sexes occur in different individuals. The male produces sperm, while the female produces ova and supports development of the embryo and foetus. This condition is described as unisexual or dioecious. It is an important basic feature of human sexual reproduction.
6. Which sequence shows the correct broad order of major events in human reproduction?
ⓐ. Birth → implantation → fertilisation → gamete formation
ⓑ. Fertilisation → gamete formation → implantation → birth
ⓒ. Gamete formation → implantation → fertilisation → birth
ⓓ. Gamete formation → fertilisation → implantation → birth
Correct Answer: Gamete formation → fertilisation → implantation → birth
Explanation: Reproduction begins with the formation of haploid gametes in the male and female. These gametes then unite during fertilisation to form a zygote. After early development, implantation occurs in the uterus, and continued development ultimately leads to birth. This sequence captures the major events in their natural biological order.
7. Which statement correctly compares human reproduction with oviparity?
ⓐ. Humans are oviparous because the embryo develops in an egg laid outside the body
ⓑ. Humans are viviparous because external fertilisation occurs before birth
ⓒ. Humans are viviparous because development occurs inside the mother rather than in an externally laid egg
ⓓ. Humans are ovoviviparous because the zygote never forms inside the female body
Correct Answer: Humans are viviparous because development occurs inside the mother rather than in an externally laid egg
Explanation: The main difference between viviparity and oviparity lies in where the embryo develops. In humans, the embryo remains inside the mother and continues development there until birth. In oviparous organisms, development occurs in eggs laid outside the body. This makes humans clearly viviparous rather than oviparous.
8. Which event directly marks sexual reproduction in humans?
ⓐ. Mitotic division of body cells
ⓑ. Shedding of old tissues from the body
ⓒ. Release of heat from metabolic reactions
ⓓ. Fusion of male and female gametes
Correct Answer: Fusion of male and female gametes
Explanation: Sexual reproduction is defined by the coming together of two gametes, one male and one female. In humans, sperm and ovum fuse to form a diploid zygote. This event brings together genetic material from two parents and distinguishes sexual reproduction from asexual reproduction. Gamete fusion is therefore the central event of the process.
9. In human reproduction, restoration of the diploid chromosome number normally occurs at the formation of the
ⓐ. zygote
ⓑ. spermatozoon
ⓒ. secondary oocyte
ⓓ. blastocyst
Correct Answer: zygote
Explanation: Human gametes are haploid, so each carries only one set of chromosomes. When the male and female gametes fuse, their chromosome sets combine and the diploid condition is restored. The immediate product of this fusion is the zygote. Later stages such as morula and blastocyst arise from that already diploid zygote.
10. Which pair correctly represents the haploid gametes involved in human sexual reproduction?
ⓐ. Primary spermatocyte and ovum
ⓑ. Zygote and spermatozoon
ⓒ. Sertoli cell and ovum
ⓓ. Spermatozoon and ovum
Correct Answer: Spermatozoon and ovum
Explanation: Sexual reproduction in humans depends on the union of two haploid gametes. The male gamete is the spermatozoon, and the female gamete is the ovum in the broad reproductive sense. Their fusion forms a diploid zygote. Cells such as Sertoli cells and primary spermatocytes are not the functional gametes that participate directly in fertilisation.
11. A species has separate male and female individuals, fertilisation occurs inside the body, and offspring are born alive. This combination indicates that the species is
ⓐ. monoecious and oviparous
ⓑ. unisexual and viviparous
ⓒ. hermaphrodite and ovoviviparous
ⓓ. asexual and viviparous
Correct Answer: unisexual and viviparous
Explanation: Separate male and female individuals indicate a unisexual reproductive pattern. Internal fertilisation means gamete fusion occurs within the female body. Live birth shows viviparity, in which development continues inside the mother before birth. Humans fit all of these features together.
12. Which set lists the major components of the human male reproductive system?
ⓐ. Testes, kidneys, ureters, urinary bladder
ⓑ. Ovaries, oviducts, uterus, vagina
ⓒ. Testes, accessory ducts, accessory glands, external genitalia
ⓓ. Seminiferous tubules, placenta, cervix, mammary glands
Correct Answer: Testes, accessory ducts, accessory glands, external genitalia
Explanation: The male reproductive system is organized into main structural groups rather than a single organ. Testes act as the primary sex organs, accessory ducts conduct sperm, accessory glands add secretions, and external genitalia help in delivery of semen. This arrangement supports sperm production, transport, and deposition. The other options include urinary or female reproductive structures.
13. The primary sex organs in human males are the
ⓐ. testes
ⓑ. seminal vesicles
ⓒ. prostate glands
ⓓ. epididymides
Correct Answer: testes
Explanation: The testes are the primary male sex organs because they produce the male gametes. They also function as endocrine organs by contributing male sex hormones. Structures such as seminal vesicles and prostate are accessory glands, while the epididymis is part of the duct system. None of them replaces the testes as the principal reproductive organs.
14. Why is the scrotum located outside the abdominal cavity?
ⓐ. It stores secretions released by accessory glands
ⓑ. It provides the main site for fertilisation
ⓒ. It helps maintain the testes at a temperature suitable for sperm formation
ⓓ. It acts as the passage through which the embryo is delivered
Correct Answer: It helps maintain the testes at a temperature suitable for sperm formation
Explanation: Sperm formation requires a temperature slightly lower than normal body temperature. The scrotum, being outside the abdominal cavity, helps maintain this cooler condition around the testes. This thermal regulation is important for normal spermatogenesis. Its role is therefore protective and functional rather than secretory or developmental.
15. In humans, the temperature inside the scrotum is usually maintained about
ⓐ. $5^\circ\mathrm{C}$ above body temperature
ⓑ. equal to normal body temperature
ⓒ. $1^\circ\mathrm{C}$ above body temperature
ⓓ. $2$-$2.5^\circ\mathrm{C}$ below body temperature
Correct Answer: $2$-$2.5^\circ\mathrm{C}$ below body temperature
Explanation: The testes function best when they are kept slightly cooler than the rest of the body. In humans, the scrotal temperature is generally about $2$-$2.5^\circ\mathrm{C}$ lower than body temperature. This difference supports efficient sperm production. A higher temperature can adversely affect normal spermatogenesis.
16. Which option correctly distinguishes testes from male accessory glands?
ⓐ. Testes mainly lubricate the urethra, whereas accessory glands form sperm
ⓑ. Testes produce sperm, whereas accessory glands mainly add secretions to semen
ⓒ. Testes store mature sperm, whereas accessory glands trigger ovulation
ⓓ. Testes guide implantation, whereas accessory glands support placental growth
Correct Answer: Testes produce sperm, whereas accessory glands mainly add secretions to semen
Explanation: The testes are the primary site of sperm production in males. Accessory glands do not form sperm; instead, they contribute fluids that become part of seminal plasma. These secretions help nourish, protect, and transport sperm. The distinction between gamete production and fluid contribution is basic to understanding male reproductive organization.
17. Which structure serves as the external genital organ that helps in delivery of semen in human males?
ⓐ. Penis
ⓑ. Testis
ⓒ. Prostate
ⓓ. Epididymis
Correct Answer: Penis
Explanation: The penis is the external male genital organ involved in copulation and insemination. It helps deliver semen into the female reproductive tract. The testis produces sperm, the prostate is an accessory gland, and the epididymis is part of the sperm-conducting pathway. Their roles are important, but none of them serves as the external copulatory organ.
18. Which group includes only male accessory glands?
ⓐ. Epididymis, urethra, penis
ⓑ. Seminal vesicles, prostate gland, bulbourethral glands
ⓒ. Testes, seminal vesicles, scrotum
ⓓ. Rete testis, vas deferens, prostate gland
Correct Answer: Seminal vesicles, prostate gland, bulbourethral glands
Explanation: Male accessory glands are the glands that add their secretions to the semen. In humans, these are the seminal vesicles, prostate gland, and bulbourethral glands. Ducts such as vas deferens and structures like testes or penis are not accessory glands. This separates glands clearly from conducting passages and primary sex organs.
19. In the male reproductive system, accessory ducts are mainly concerned with
ⓐ. producing the female gamete
ⓑ. secreting placental hormones
ⓒ. transporting sperm from the testes toward the exterior
ⓓ. nourishing the embryo during pregnancy
Correct Answer: transporting sperm from the testes toward the exterior
Explanation: Accessory ducts form the passage through which sperm move after being produced in the testes. They conduct sperm step by step toward the outside of the body. This transport function is different from the secretory role of accessory glands and the sperm-producing role of testes. The duct system is therefore essential for sperm delivery, not sperm formation.
20. Which statement best describes the broad functional organization of the male reproductive system?
ⓐ. Accessory glands produce sperm, and testes deliver them through the uterus
ⓑ. Penis forms sperm, and accessory ducts store the embryo for development
ⓒ. Accessory ducts release ova, while testes provide the site of fertilisation
ⓓ. Testes produce sperm, accessory ducts conduct them, and the penis helps in insemination
Correct Answer: Testes produce sperm, accessory ducts conduct them, and the penis helps in insemination
Explanation: The male reproductive system works as a coordinated set of structures with different roles. Testes are responsible for sperm production, accessory ducts carry the sperm forward, and the penis helps deposit semen during copulation. Accessory glands also contribute fluids that support sperm function. This division of labour gives the system its overall reproductive efficiency.
