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Q1. Sperms are:
Motile germ-cellsSperms are the male germ-cells (gametes) in animals. They are microscopic, motile cells with a flagellum (tail) that allows them to swim through the female reproductive tract to reach the egg. They are not female gametes (eggs are female), nor are they large or immobile—the female egg is large and non-motile.
Q2. Puberty prepares the body for:
ReproductionPuberty is the phase of life when the human body undergoes physical and physiological changes that enable it to reproduce. Reproductive tissues mature, secondary sexual characteristics develop, and the body becomes capable of producing gametes (sperms in males, eggs in females). Respiration, digestion, and general growth occur throughout life, but puberty specifically prepares the body for reproduction.
Q3. Physical changes during puberty act as:
Signals of sexual maturityPhysical changes during puberty—such as voice deepening, facial hair, breast development, and growth of pubic hair—are external signals that indicate an individual has reached sexual maturity. These changes inform others (especially potential mates) of reproductive readiness. They are not disorders, diseases, or signs of ageing (ageing occurs much later).
Q4. The period when reproductive tissues begin to mature is called:
PubertyPuberty is the specific period during which the reproductive tissues (ovaries in females, testes in males) begin to mature, and secondary sexual characteristics appear. Adolescence is the broader transitional stage from childhood to adulthood (ages ~10–19), which includes puberty but also psychological and social changes. Infancy and childhood are earlier growth stages before reproductive maturation begins.
Q5. In flowering plants, germ-cells are transferred by:
External releaseIn flowering plants, germ-cells are transferred through external release of pollen (containing male germ-cells) into the environment. Pollen is carried by wind, water, or animals to the stigma of another flower. This is not internal fertilisation (animals), budding (asexual), or mating (animals). The male gametes are released from anthers externally.
Q6. Sexual maturation occurs because:
Reproductive tissues matureSexual maturation is defined as the process by which the reproductive organs (testes in males, ovaries in females) develop and become capable of producing functional gametes (sperms and eggs). This is accompanied by hormonal changes. Growth does not stop; in fact, a growth spurt occurs during puberty. Cells continue dividing; reproductive tissue maturation is the cause, not the result.
Q7. Which glands add secretions to sperms?
Prostate and seminal vesiclesThe prostate gland and seminal vesicles are accessory glands in the male reproductive system. They add secretions that together with sperms form semen. These secretions provide nutrients (fructose for energy), buffer against vaginal acidity, and fluids for sperm transport. Sweat glands, pancreas, liver, thyroid, and adrenal glands have other functions unrelated to semen formation.
Q8. The organ that transfers sperms in humans is:
PenisThe penis is the external male reproductive organ that transfers sperms (semen) into the female reproductive tract during sexual intercourse. The testes produce sperms; the urethra is the passage tube inside the penis; the scrotum holds the testes. The penis is the delivering organ.
Q9. Germ-cells in humans are specialised for:
Sexual reproductionGerm-cells (sperms and eggs) are specialised cells whose sole function is sexual reproduction. They are haploid (contain half the chromosomes) and are designed to fuse during fertilisation to form a zygote. They do not participate in excretion, repair of body tissues (somatic cells do that), or general growth of the body.
Q10. Adolescence is marked by:
Growth and sexual maturationAdolescence is the transitional period from childhood to adulthood characterised by rapid physical growth (height, weight, muscle mass) and sexual maturation (development of reproductive organs and secondary sexual characteristics). Ageing occurs later in life; “only growth” is incomplete; “no body changes” is false.
Q11. Breast-feeding occurs because:
Female reproductive organs matureBreast-feeding (lactation) becomes possible after female reproductive organs mature during puberty. The breasts (mammary glands) develop under the influence of female hormones and produce milk after childbirth. This is directly linked to female reproductive maturation. Maturation of sperms, male organs, or testes is irrelevant to breast-feeding.
Q12. Secretions added to sperms mainly help in:
Transport and nutritionAccessory gland secretions (from seminal vesicles, prostate, bulbourethral glands) form seminal fluid. They provide a fluid medium for sperm transport, supply nutrients (fructose) for energy, neutralise vaginal acidity, and aid sperm motility. They do not kill sperms, reduce movement, or prevent fertilisation—they facilitate fertilisation.
Q13. Puberty changes do NOT occur:
At the same time in everyonePuberty changes occur at different ages in different individuals due to genetic, nutritional, and environmental factors. Some may start at age 10, others at 14. Changes also occur gradually over months and years, not suddenly or at a fixed universal age. They are not synchronised across all people.
Q14. Sperms are microscopic cells that:
Move activelySperms are highly motile cells equipped with a flagellum that beats to propel them through the female reproductive tract toward the egg. They do contain DNA (haploid nucleus) but have minimal food reserves (they rely on seminal fluid for energy). They are not immobile—motility is essential for fertilisation.
Q15. Sexual maturity must be identifiable to:
Other individualsSexual maturity is signalled through physical changes (secondary sexual characteristics) so that other individuals of the same species can identify reproductively ready mates. This facilitates mating and reproduction. Plants, cells, and bacteria do not need to identify sexual maturity in this social/behavioural sense.
Q16. Sperms are produced in the:
TestesThe testes (testicles) are the male gonads responsible for producing sperms through spermatogenesis. The prostate gland adds secretions; the vas deferens is a duct that transports sperms; the penis is the external organ for delivery. Production occurs only in the testes.
Q17. The male reproductive system consists of organs that:
Produce and deliver germ-cellsThe male reproductive system has two primary functions: (1) production of male germ-cells (sperms) in the testes, and (2) delivery of these sperms into the female reproductive tract via the penis. It does not circulate blood (circulatory system) or digest food (digestive system). It does more than just store sperms.
Q18. Sexual maturity is necessary for:
ReproductionSexual maturity is the stage when an organism’s reproductive organs become functional and capable of producing gametes. This is necessary for sexual reproduction to occur. Digestion, growth, and respiration occur regardless of sexual maturity and are not dependent on it.
Q19. Cutting open soaked seeds helps to:
Identify seed partsSoaking seeds softens the seed coat, making it easier to cut open and observe internal structures. This allows students or botanists to identify the embryo, cotyledons (seed leaves), and seed coat. It is a dissection technique for study, not for removal, prevention of growth, or destruction.
Q20. Which change is common to both boys and girls during puberty?
Hair growth in armpitsAxillary (armpit) hair growth occurs in both boys and girls during puberty due to increased androgen levels. Facial hair growth and voice cracking are primarily male changes; breast development is primarily female (though minor breast tissue growth can occur in boys temporarily). Armpit hair is a universal secondary sexual characteristic.
Q21. Oily skin and pimples during teenage years occur due to:
Sexual maturationDuring puberty, increased production of sex hormones (androgens like testosterone) stimulates sebaceous glands in the skin to produce more sebum (oil). Excess sebum can clog pores, leading to acne (pimples). This is a normal physiological consequence of sexual maturation, not primarily due to poor hygiene, infection, or lack of water.
Q22. In humans, the baby develops inside the:
Mother’s body (uterus)In humans, the fertilised egg (zygote) implants and develops into a foetus inside the uterus (womb), which is part of the mother’s body. The ovary releases eggs; the fallopian tube is where fertilisation typically occurs; the urinary bladder stores urine. The uterus provides protection, nutrition, and waste removal for the developing baby.
Q23. Soaking Bengal gram seeds helps to:
Initiate germinationSoaking seeds in water softens the seed coat, activates enzymes, and allows water absorption (imbibition), which triggers metabolic processes and initiates germination. The embryo resumes growth. Soaking does not prevent germination, kill the embryo, or harden the seed coat—it does the opposite.
Q24. The scrotum helps in:
Maintaining suitable temperatureThe scrotum is a pouch of skin that holds the testes outside the abdominal cavity. This location keeps the testes at a temperature about 2–3°C lower than body temperature, which is essential for normal sperm production (spermatogenesis). It does not produce hormones (testes do), does not directly aid fertilisation, and does not store urine (urinary bladder does).
Q25. Formation of sperms is known as:
SpermatogenesisSpermatogenesis is the process of sperm formation that occurs in the seminiferous tubules of the testes. Fertilisation is the fusion of sperm and egg; ovulation is the release of an egg from the ovary; menstruation is the shedding of the uterine lining. Only spermatogenesis refers specifically to sperm production.
Q26. The main role of the male reproductive system is to:
Produce and deliver spermsThe primary functions of the male reproductive system are (1) production of male gametes (sperms) and (2) delivery of these sperms into the female reproductive tract. Hormone production (testosterone) occurs as a secondary function. Urine production is renal; oxygen transport is circulatory.
Q27. The study of reproduction in humans mainly focuses on:
Sexual reproductionHuman reproduction is exclusively sexual, involving the fusion of male and female gametes. The study focuses on the anatomy and physiology of male and female reproductive systems, gamete formation, fertilisation, pregnancy, and childbirth. Humans do not reproduce asexually; growth and ageing are separate topics.
Q28. Sexual reproduction requires joining of:
Germ-cells from two individualsSexual reproduction is defined by the fusion (joining) of male and female germ-cells (gametes) from two different individuals (or at least two different gamete sources). This produces a zygote with a unique combination of genes. Two organs, tissues, or embryos are not what join in sexual reproduction.
Q29. Sperm formation requires a temperature:
Lower than body temperatureSpermatogenesis requires a temperature approximately 2–3°C lower than normal body temperature (37°C). This is why the testes are located outside the body in the scrotum. Higher temperatures can impair or stop sperm production. This is a unique requirement among body processes.
Q30. Changes occurring in early teenage years that affect appearance are called:
Sexual maturationThe physical changes in early teenage years—growth spurt, voice changes, facial/body hair, breast development, etc.—are collectively called sexual maturation (or puberty). These changes are driven by sex hormones and prepare the body for reproduction. They are not merely growth changes (which occur throughout childhood), not ageing (old age), and not disease symptoms.
Q31. The fluid containing sperms is called:
SemenSemen is the fluid ejaculated during male orgasm. It contains sperms (produced in testes) mixed with secretions from the seminal vesicles, prostate gland, and bulbourethral glands. Urine is waste from kidneys; blood transports oxygen and nutrients; lymph is part of the immune system.
Q32. In humans, germ-cells are transferred by:
Internal transferIn humans, germ-cells are transferred internally. The male deposits semen containing sperms into the female reproductive tract during sexual intercourse. Fertilisation then occurs inside the female’s body (internal fertilisation). Water, wind, and external fertilisation are mechanisms seen in some aquatic animals and plants, not humans.
Q33. Testosterone is responsible for:
Male secondary sexual charactersTestosterone is the primary male sex hormone produced by the testes. It is responsible for the development of male secondary sexual characteristics during puberty: facial and body hair, voice deepening, increased muscle mass, broadening of shoulders, and sperm production. It does not affect digestion, female features (estrogen does), or egg formation.
Q34. Differences in puberty timing among individuals show:
Natural variationThe age at which puberty begins varies naturally among individuals due to genetic factors, nutrition, overall health, and environmental conditions. Some start at 9–10 years, others at 13–14 or later. This is normal biological variation, not a disease, uniformity (which would mean everyone same), or injury.
Q35. During puberty, body resources are directed towards:
Growth first, then reproductionDuring early puberty, the body prioritises rapid physical growth (height, muscle, bone density). Once growth is near completion, resources shift toward reproductive functions (gamete production, sexual behaviours). This sequence ensures that individuals reach a sufficient size before investing energy in reproduction. The body does not ignore growth or focus only on respiration/digestion.
Q36. Humans reproduce mainly by:
Sexual reproductionHumans reproduce exclusively through sexual reproduction, involving the fusion of male (sperm) and female (egg) gametes. Asexual reproduction, budding, and vegetative propagation do not occur in humans. Sexual reproduction produces genetically diverse offspring.
Q37. Differences in hair growth and body features among people are due to:
Natural variationDifferences in hair growth patterns, body shape, height, skin colour, and other features among humans are due to natural genetic variation, hormonal differences, and environmental factors. This is normal and expected. Injury may cause localised changes; uniformity would mean everyone identical; disease causes abnormal changes, not normal variation.
Q38. Thick hair growth in armpits and genital area begins during:
AdolescencePubic and axillary (armpit) hair growth begins during adolescence (puberty) in both males and females, driven by increased androgen levels. Infants have fine, light hair (vellus); childhood has little to no pubic/axillary hair; old age may see hair thinning or loss, not initial growth. Adolescence is the period when these secondary sexual characteristics appear.
Q39. Puberty does not occur:
Suddenly in one dayPuberty is a gradual process that occurs over several months to years (typically ages 10–14 for girls, 12–16 for boys). It does not happen suddenly in one day. Changes occur at different ages for different individuals, and they happen progressively, not abruptly.
Q40. Urethra acts as a common passage for:
Urine and spermsIn human males, the urethra is a common passage for both urine (from the urinary bladder) and semen (containing sperms). However, they do not pass simultaneously; a sphincter prevents urine from passing during ejaculation. Air does not pass through the urethra (that is the trachea); “semen only” is incomplete; blood does not pass.
Q41. Sperms are carried from testes to urethra by:
Vas deferensThe vas deferens (also called ductus deferens) is a long muscular tube that transports mature sperms from the epididymis (attached to testes) to the urethra during ejaculation. The penis is the external organ; the scrotum holds testes; the prostate adds secretions but does not transport sperms.
Q42. Covering soaked seeds with a wet cloth ensures:
Continuous moistureCovering soaked seeds with a wet cloth maintains a humid environment, preventing the seeds from drying out. Continuous moisture is essential for germination because water activates enzymes, softens the seed coat, and supports metabolic processes. Excess heat, dry conditions, or seed dormancy are not promoted by this practice.
Q43. Male secondary sexual characters include:
Voice cracking (deepening)Male secondary sexual characteristics include facial and body hair growth, voice deepening (often preceded by cracking), increased muscle mass, broadening of shoulders, and Adam’s apple development. Menstruation, breast development, and ovulation are female secondary sexual characteristics or processes.
Q44. Increase in height and weight with age is called:
GrowthGrowth refers to an increase in physical dimensions—height, weight, and body mass—over time. Maturation refers to the process of becoming functionally mature (including sexual maturation). Development encompasses both growth and differentiation. Reproduction is the production of offspring. The simple increase in height and weight is specifically called growth.
Q45. Reproductive organs mature mainly when:
Body growth slows downReproductive organs mature near the end of the adolescent growth spurt. As the rapid increase in height and weight begins to slow down, the reproductive system completes its maturation (gonads become functional, menstrual cycles begin in females, sperm production in males). Birth is far too early; old age is too late.
Q46. Sexual reproduction helps in:
Producing variationSexual reproduction generates genetic variation through crossing over, independent assortment during meiosis, and random fusion of gametes from two parents. This produces offspring that are genetically different from each other and from parents. Identical offspring come from asexual reproduction; evolution requires variation, so sexual reproduction promotes, not prevents, evolution.
Q47. Increase in breast size during puberty occurs in:
Girls onlyBreast development (thelarche) is a female secondary sexual characteristic triggered by estrogen during puberty. While boys may experience temporary minor breast tissue enlargement (gynecomastia) due to hormonal fluctuations, significant and permanent breast size increase occurs only in girls. Elderly women may have breast changes but not due to puberty.
Q48. The hormone secreted by testes is:
TestosteroneThe testes (Leydig cells) secrete testosterone, the primary male sex hormone responsible for male secondary sexual characteristics and spermatogenesis. Insulin is secreted by the pancreas; estrogen and progesterone are female sex hormones secreted by the ovaries.
Q49. Voice cracking is observed mainly in:
BoysVoice cracking (unpredictable changes in pitch) occurs mainly in boys during puberty as the larynx (voice box) grows and the vocal cords lengthen and thicken under the influence of testosterone. The voice eventually deepens. Girls’ voices also change but more smoothly, without the characteristic cracking seen in boys.
Q50. Testes are located outside the abdominal cavity to:
Maintain lower temperatureThe testes are located outside the abdominal cavity in the scrotum to maintain a temperature approximately 2–3°C lower than core body temperature. This lower temperature is essential for normal spermatogenesis (sperm production). Higher intra-abdominal temperatures would impair or halt sperm production. This is not for organ protection, blood supply increase, or space saving.