1. Choose the correct option.
a. In asexual reproduction, only one parent is needed, resulting in offspring that are genetically identical to the parent.
Which method of asexual reproduction takes place in Spirogyra?
i. Spore formation
ii. Vegetative propagation
iii. Fragmentation
iv. Budding
Answer: iii. Fragmentation
b. A potato plant does not produce seeds, but it produces a new plant by means of vegetative propagation.
Which type of modified stem is the potato plant?
i. Runner
ii. Bulb
iii. Rhizome
iv. Tuber
Answer: iv. Tuber
c. Fatima was studying the various parts of a hibiscus flower. She noticed a knob-like structure at the top of a long narrow tube which was sticky in nature. This sticky knob-like structure is the:
i. Stigma
ii. Ovary
iii. Pollen grains
iv. Style
Answer: i. Stigma
d. Which of the following is a dicot seed?
i. Banana
ii. Wheat
iii. Tomato
iv. Rice
Answer: iii. Tomato
2. Assertion and Reasoning Questions
a. Assertion (A): Cotton seeds are dispersed by wind.
Reason (R): Cotton seeds have wings.
Answer: (a) Assertion (A) is true, but Reason (R) is false.
b. Assertion (A): A bisexual flower has both the male and the female reproductive parts.
Reason (R): The male gamete is found inside the ovule and the female gamete is found inside the pollen grains.
Answer: (c) Assertion (A) is true, but Reason (R) is false.
3. Answer the following questions in one sentence.
a. What type of reproduction is seen in Rhizopus?
Answer: Spore formation.
b. What is the main function of petals?
Answer: The main function of petals is to attract insects for pollination.
c. In which part of a flower does fertilisation occur?
Answer: Fertilisation occurs inside the ovary.
d. Which structure produces the female gamete in ferns?
Answer: Archegonium produces the female gamete in ferns.
4. Answer the following questions in 2–3 sentences.
a. It is very important that seeds get scattered away from the parent plant. Justify this statement.
Answer: Seeds must scatter away from the parent plant to avoid competition for sunlight, water, and nutrients. It also helps plants spread to new areas and grow in different places.
b. Man has taken advantage of the natural mode of propagation in plants and adapted them to use in his gardens, nurseries, and in agriculture by artificial propagation. Give two advantages of artificial propagation.
Answer:
- It helps grow plants with the same good qualities as the parent plant.
- It allows the rapid production of many plants in a short time.
5. Answer the following questions in 3–4 sentences.
a. Saurav cut a bud-bearing stem of a rose plant and planted it in the soil. He watered the stem regularly. What will he observe after a few days? Will the plant be identical to the parent plant? Why?
Answer: After a few days, Saurav will observe that new roots and shoots grow from the stem cutting. Yes, the new rose plant will be identical to the parent plant because it was formed by vegetative propagation, where no seeds are used and only one parent is involved.
b. An artificial method of vegetative propagation was undertaken in laboratories. It was based on the fact that a new plant can be grown from a single cell. Name this artificial method of vegetative propagation. Explain how this process takes place.
Answer: The method is called Tissue Culture. In this process, a small piece of plant tissue or even a single cell is placed in a nutrient medium under sterile conditions. It grows and develops into a new plant that is identical to the parent plant.