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Q1. What happens when the male and female gamete are fused together? What does it develop into?

Solution

A zygote is formed by the fusion of male and female gamete. It develops into an embryo.

Q2. From which part of flower do the below parts develop:(a) Fruit(b) Seeds

Solution

(a) Fruit develops from ovary(b) Seeds develop from ovules

Q3. Name two plants which can be propagated through:(i) stem cutting(ii) Roots

Solution

(i) Rose and Champa(ii) Sweet potato and Dahlia.

Q4. What do you understand by:(a) unisexual flowers(b) bisexual flowers

Solution

(a) The flowers which contain either only the pistil or only the stamens are called unisexual flowers.(b) The flowers which contain both stamens and pistil are called bisexual flowers

Q5. Name the following: (i) Parts of a stamen. (ii) The process in which the pollen of a flower lands on the stigma of a another plant (of the same kind) situated far away. (iii) The process of fusion of male and female gametes to form zygote.

Solution

(i) Filament and anther (ii) Cross-pollination (iii) Fertilization

Q6. Explain the conditions necessary for the seed germination.

Solution

Conditions necessary before seed germination are as follows: 1. Water: Dormant seeds are dry and contain only 5-10% of water. In the presence of sufficient water, seeds swell, the seed coat breaks. The plumule develops into the shoot system and the radicle forms the root system. 2. Oxygen: Plants need oxygen for respiration. Oxygen helps plants to release energy from the stored food in cotyledons. 3. Temperature: Every plant grows at a suitable or optimum temperature. Optimum temperature is different for every plant. The range of optimum temperature is 10 to 30 ⁰C.

Q7. What would happen if all the seeds of a plant were to fall at the same place and grow there?

Solution

If all seeds of a plant were to fall at the same place and grow there, it would result in severe competition for sunlight, water, minerals and space. As a result, the seeds would not grow into healthy plants.

Q8. Name three hard fruits.

Solution

Walnuts, almonds and peach are examples of hard fruits

Q9. Give two examples each of:(a) Fruits which are fleshy and juicy.(b) Seeds dispersed when fruits burst with sudden jerks

Solution

(a) Mango, apple and orange. (Any two)(b) Castor and balsam

Q10. Why do farmer prefer the method of vegetative reproduction for growing plants

Solution

Producing plants by vegetative propagation is faster than growing plants from seeds. The method of vegetative reproduction does not depend on external factors such as temperature, wind, animals, etc.; therefore it is also certain process. Therefore, farmers prefer the method of vegetative reproduction for growing plants.

Q11. Flowers are generally very colourful and fragrant. How is this important for pollination?

Solution

Flowers are generally very colourful and fragrant so as to attract insects. Insects are very important in bringing about pollination. Insects visit flowers and carry away pollens on their bodies. When they visit another flower of the same kind, some of the pollens lands on the stigma of that flower and brings about pollination.

Q12. (a) Name three agents of seed and fruit dispersal.(b) Which type of seeds gets dispersed by water? Give an example.

Solution

(a) Wind, water and animals are the agents of seed and fruit dispersal.(b) The fruits or seeds dispersed by water usually develop floating ability in the form of spongy or fibrous outer coat. Example - Coconut.

Q13. (a) What do you understand by seed dispersal?(b) What happens to the seeds when fruits burst with sudden jerks?

Solution

(a) Seed dispersal refers to spread of seeds away from parent plant to a new growing location in order to prevent overcrowding.(b) When the fruits burst with sudden jerks, the seeds are dispersed and are scattered far from the parent plant.

Q14. Name the following:(i) A part of the stem/branch at which a leaf arises(ii) Buds in the axil of leaves which develop into shoots

Solution

(i) Node(ii) Vegetative buds

Q15. A boy cut a few pieces of a potato and buried each of them in soil. After watering the pieces regularly for a few days, he observed that potato plant sprouted from a few pieces, but not the rest. Why?

Solution

Plant will sprout only from those pieces which had an eye (bud) in them. The pieces from which the plant did not sprout lacked a bud in them, from which new plant can develop.

Q16. What is hybridisation?

Solution

The whole process of producing better seeds or crops from the existing seeds or plants is called hybridisation.

Q17. Name the following:(i) Two hard fruits.(ii) The protective structure enclosing the embryo.

Solution

(i) Almond and walnut(ii) Seed coat

Q18. What is vegetative propagation. Explain any one process of artificial vegetative propagation.

Solution

Vegetative Propagation: Several plants are capable of producing naturally through their roots, stems and leaves. Such type of reproduction is called vegetative reproduction. Layering is one of the methods of artificial vegetative propagation. In this method, the lower branch of a plant is chosen. A ring of bark is removed from a portion of the stem. The same portion is then bent and covered with the soil for a few days. During these days, new roots develop on the branch. The branch is then separated from the parent plant and allowed to grow as individual plant.

Q19. Write two examples of plants producing:(i) Unisexual flowers(ii) Bisexual flowers

Solution

(i) Corn, papaya, cucumber(ii) Mustard, rose, petunia(Any two of each)

Q20. What do you understand by pollination?

Solution

The transfer of pollen from the anther to the stigma of a flower is called pollination.

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