Class-5 Science

    

Chapter 1: Plant reproduction

III Answer the following questions in one sentence.

1.    1. What does a seed need to germinate?

Ans. A seed needs air, water and warmth to germinate.

2  2.    Name a plant which form a new plant from its bulb.

Ans. Lily plant forms a new plant from its bulb.

3.3.  When is a rabi crop grown?

Ans. Rabi crop is grown in the winter season.

4.4.    When is a kharif crop grown?

Ans. . Kharif crop is grown in the rainy season.

5.5.    What are weeds?

Ans. Weeds are wild, unwanted plants that grow in the fields.

IV. Answer the questions.

1.1.    Explain the process of germination of a seed with a labelled diagram.

Ans. The embryo in a seed begins to grow when the seed obtains the required amount of air, water, and warmth. The seed grows as it absorbs water. The seed coat splits as a result, and the root emerges. The root grows downward into the soil and absorbs water. The shoot grows upwards towards light and forms the stem and leaves.

Diagram:

 

 

2.2.    Describe any two ways of seed dispersal.

Ans. Seeds are dispersed by wind, animals, explosion and water. The seeds of all grasses are very light and are carried away by the wind. Dandelions, desert roses, and milkweed seeds resemble parachutes. Such seeds are carried away from the mother plant by the wind. The seeds of the Indian elm tree glide in the wind. When it rains, some of these seeds fall to the ground, get covered by soil and germinate. The dried fruits of some plants, such as the ladies’ finger, explode, dispersing the seeds away from the mother plant.

3.3.    Do flowering plants produce new plants only through seeds?

Ans. Flowering plants form new plants from their roots, stems or leaves. The sweet potato and the yam plants form new plants from their roots. Plants such as tea, rose, marigold and grape can be grown from stem cuttings. Plants such as lily and onion form bulbs. The bulbs grow into new plants. The leaves of plants such as Begonia and Bryophyllum produce new plants.

4.4.    Describe how different non-flowering plants reproduce.

Ans. Trees such as cedars, firs and pines produce cones with seeds. The seeds give rise to new plants. Ferns produce spreads on the lower surface of their leaves. Spores fall on the ground, and give rise to new plants.

5.5.    List the steps followed by farmers to grow crops.

Ans. Farmers follow the steps given below for a good and healthy crop:

a. till the soil and add fertilisers to the field.

b. sow seeds of good quality.

c. irrigate the crops at regular intervals.

d. remove weeds from the fields.

e. spray pesticides.

f. protect the crop from grazing animals.

g. harvest the crop

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