CBSE Class 7 Science Advanced Biology Reproduction in Plants MCQs Set 01

Answer: (a) bulb

Explanation:
1. Onion is an underground stem with food stored in fleshy leaves, and it bears buds.
2. Such a food-storing, bud-bearing structure is a bulb.
3. A tuber is like a potato, budding is an artificial method and a runner creeps over the ground.

Teacher's Note:
1. Garlic is another bulb.
2. Bulb, tuber and runner are all natural stem propagation.

Answer: (b) layering

Explanation:
1. In climbing rose a bent branch touches the soil and develops roots there.
2. This method of getting a new plant from a bent branch is layering.

Teacher's Note:
1. In layering the branch stays attached to the parent till roots form.
2. Cutting needs a piece separated from the plant first.

Answer: (d) Stamen

Explanation:
1. Calyx (sepals) protects the bud and corolla (petals) attracts insects.
2. Pistil is the female part.
3. The stamen (anther and filament) makes pollen grains and is the male organ.

Teacher's Note:
1. Stamen is also called androecium.
2. Pistil is called gynoecium.

Answer: (a) wind

Explanation:
1. Dandelion seeds are very light.
2. Very light seeds are carried far away by moving air, so dispersal is by wind.

Teacher's Note:
1. The book prints 'pollination' here, but the options describe dispersal, so the word was corrected.
2. Light seeds with fluffy parts are wind dispersed.

Answer: (d) Runner

Explanation:
1. Artificial methods are done by people: cutting, grafting, budding and layering.
2. A runner is a weak stem that creeps and roots by itself, so it is natural propagation.

Teacher's Note:
1. Natural: root, bulb, tuber, runner, leaf.
2. Artificial: cutting, grafting, budding, layering.

Answer: (b) Bryophyllum

Explanation:
1. Small buds grow on the notches of the Bryophyllum leaf and grow into plantlets.
2. Climbing rose uses layering, onion is a bulb and potato a stem tuber, so the answer is Bryophyllum.

Teacher's Note:
1. Only a few plants propagate by leaf.
2. Bryophyllum is the standard example.

Answer: (a) fruit

Explanation:
1. After fertilization the ovule becomes the seed.
2. The ovary that holds the ovule becomes the fruit.

Teacher's Note:
1. Remember: ovary to fruit, ovule to seed.
2. The zygote forms the embryo inside the seed.

Answer: (a) A-(iii), B-(iv), C-(i), D-(ii)

Explanation:
1. Bulb: onion, so A-(iii).
2. Tuber: potato, so B-(iv).
3. Root: sweet potato, so C-(i).
4. Leaf: Bryophyllum, so D-(ii).
5. The pairing A-(iii), B-(iv), C-(i), D-(ii) is option (a).

Teacher's Note:
1. Each organ gives a typical example.
2. Check the pairs one by one.

Answer: (b) After fertilization, ovary will become seed.

Explanation:
1. Statements (a), (c) and (d) are correct.
2. After fertilization the ovary becomes the fruit, not the seed. The ovule becomes the seed, so (b) is wrong.

Teacher's Note:
1. Read each statement and test it.
2. Do not mix up ovary and ovule.

Answer: (d) A is false, but R is true.

Explanation:
1. Seed forms from the ovule only after fertilization, so it is a post-fertilization event and A is false.
2. R says the ovule becomes the seed after fertilization, which is true.
3. So A is false but R is true.

Teacher's Note:
1. Pre-fertilization: pollination. Post-fertilization: seed and fruit formation.
2. Test A and R separately first.