In-text Questions — Sexual Reproduction — How do Organisms Reproduce?

1. 12 marksNCERT Cl-10 Science, In-text Qs after §7.3.3, Q1

   How is the process of pollination different from fertilisation?

   Hint. One process moves pollen to a new location; the other is what happens once it gets there.

   Step 1 — Define pollination. Pollination is the transfer of pollen from the anther (stamen) to the stigma, either within the same flower (self-pollination) or between different flowers (cross-pollination).

   Step 2 — Define fertilisation. Fertilisation is the fusion of the male germ-cell (carried down the pollen tube through the style) with the female gamete in the ovule, forming a zygote.

   Step 3 — State the relationship. Pollination must happen first, since fertilisation can only occur once the pollen has reached the stigma and grown a tube down to the ovary.

   ✦ Answer: Pollination is the transfer of pollen from anther to stigma; fertilisation is the later fusion of male and female germ-cells to form a zygote, which can only happen after pollination.

   Where students slip. Treating the two words as interchangeable — pollination is just the pollen's journey to the stigma; fertilisation is the actual joining of germ-cells that follows it.

2. 22 marksNCERT Cl-10 Science, In-text Qs after §7.3.3, Q2

   What is the role of the seminal vesicles and the prostate gland?

   Hint. Sperm alone can't travel well — think about what these glands add to help them along.

   Step 1 — Recall where these glands sit. The seminal vesicles and prostate gland add their secretions along the path of the vas deferens.

   Step 2 — State what their secretions do. Since these secretions put the sperm into a fluid, this makes their transport easier and also provides them with nutrition.

   ✦ Answer: The seminal vesicles and prostate gland add fluid secretions to the sperm, making them easier to transport and providing nutrition — together forming semen.

   Where students slip. Saying these glands produce the sperm themselves — sperm are produced in the testes; these glands only add the fluid that carries and nourishes the sperm.

3. 32 marksNCERT Cl-10 Science, In-text Qs after §7.3.3, Q3

   What are the changes seen in girls at the time of puberty?

   Hint. Separate the changes shared with boys from the ones specific to girls.

   Step 1 — Shared changes. Both boys and girls develop thicker hair in the armpits and genital area, thinner hair on the arms/legs/face, and oilier skin.

   Step 2 — Changes specific to girls. Breast size begins to increase, the skin of the nipples darkens, and girls begin to menstruate, since these are the changes tied specifically to female sexual maturation.

   ✦ Answer: Along with the shared changes (body hair, oilier skin), girls specifically experience increasing breast size, darkening of the nipple skin, and the onset of menstruation.

   Where students slip. Listing only the changes shared with boys — the question specifically asks about changes seen in girls, so the girl-specific changes (breast development, menstruation) must be included.

4. 42 marksNCERT Cl-10 Science, In-text Qs after §7.3.3, Q4

   How does the embryo get nourishment inside the mother's body?

   Hint. Name the special structure embedded in the uterine wall that connects mother and embryo.

   Step 1 — Name the structure. The embryo gets nutrition through a special tissue called the placenta, a disc embedded in the uterine wall.

   Step 2 — Describe how it works. The placenta has villi on the embryo's side, surrounded by blood spaces on the mother's side, since this arrangement gives a large surface area for glucose and oxygen to pass from mother to embryo.

   Step 3 — Note the reverse traffic. The placenta also allows waste substances generated by the developing embryo to pass into the mother's blood for removal.

   ✦ Answer: Through the placenta — a disc in the uterine wall with villi (embryo's side) surrounded by maternal blood spaces, giving a large surface for glucose and oxygen to pass to the embryo, and waste to pass back to the mother.

   Where students slip. Saying the mother's and embryo's blood mix directly — they don't; the placenta's villi and surrounding blood spaces allow exchange across a large surface without the two blood supplies actually mixing.

5. 52 marksNCERT Cl-10 Science, In-text Qs after §7.3.3, Q5

   If a woman is using a copper-T, will it help in protecting her from sexually transmitted diseases?

   Hint. Copper-T works inside the uterus, well past the point where an infection-causing organism would already have entered the body.

   Step 1 — Recall what a copper-T actually does. A copper-T is placed in the uterus to prevent pregnancy — it doesn't create any barrier between the two partners' bodies during intercourse.

   Step 2 — Contrast with what prevents STIs. Only a physical barrier, such as a condom, blocks the transmission of infection-causing organisms during the sexual act.

   Step 3 — State the conclusion. Since the copper-T only acts inside the uterus and does nothing to block transmission during intercourse, it offers no protection against sexually transmitted diseases.

   ✦ Answer: No — a copper-T only prevents pregnancy; it creates no physical barrier during intercourse, so it does not protect against sexually transmitted diseases. Only barrier methods like condoms do that.

   Where students slip. Assuming any effective contraceptive also prevents STIs — pregnancy prevention and disease prevention are separate functions; only barrier methods that physically block contact achieve the second one.

Solutions written by the tuition.in editorial team and checked against the NCERT Class 10 Science textbook, Reprint 2026-27 (jesc107.pdf) — three in-text question sets (12 questions total) plus one end-of-chapter Exercise (11 questions, not 17 as some older manifests claim). Unchanged by rationalisation.. Questions are referenced from the NCERT textbook for identification.