NCERT Exemplar Solutions Class 7 Science Reproduction in Plants

Multiple Choice Questions..................

Question 1:  Which of the following parts of a plant take part in sexual reproduction?

(i) Flower

(ii) Seed

(iii) Fruit

(iv) Branch Choose the correct answer from below.

(a) (i) and (ii)

(b) (i), (ii) and (iii)

(c) (iii) and (iv)

(d) (ii), (iii) and (iv) 

Solution 1: (b) (i), (ii) and (iii) 

Sexual reproduction tasks are carried out by flowers. The ovaries grow into fruits after fertilization and seeds develop from the ovules.

Question 2:  Lila observed that a pond with clear water was covered up with green algae within a week. By which method of reproduction did the algae spread so rapidly?

(a) Budding

(b) Sexual reproduction

(c) Fragmentation

(d) Pollination 

Solution 2:  (c) Fragmentation                                                              

An alga splits up into two pieces or more. These bits or fragments develop into new individuals. This method continues and in a brief amount of time they cover a wide field.

Question 3:  Seeds of drumstick and maple are carried to long distances by wind because they possess

(a) winged seeds

(b) large and hairy seeds

(c) long and ridged fruits

(d) spiny seeds 

Solution 3:  (a) winged seeds

Drumstick and maple seeds have wings that allow them to be carried away quickly by the breeze. Similar seeds and fruits have certain peculiar features when they are taken away in a specific way (by wind, water or animal).

Question 4:  The ‘eye’ of the potato plant is what

(a) the root is to any plant.

(b) the bud is to a flower.

(c) the bud is to Bryophyllum leaf.

(d) the anther is to stamen 

Solution 4:  (c) the bud is to Bryophyllum leaf.

The vegetative bud that grows from stem tuber nodes is the eye of the potato. The bryophyllum leaf has vegetative buds, much like potatoes.

Question 5:  The ovaries of different flowers may contain

(a) only one ovule

(b) many ovules

(c) one to many ovules

(d) only two ovules 

Solution 5:  (c) one to many ovules

The ovaries of different flowers may contain one to many ovules.

Question 6:  Which of the following statements is/are true for sexual reproduction in plants?

(i) Plants are obtained from seeds.

(ii) Two plants are always essential.

(iii) Fertilisation can occur only after pollination.

(iv) Only insects are agents of pollination.

Choose from the options given below.

(a) (i) and (iii)

(b) (i) only

(c) (ii) and (iii)

(d) (i) and (iv) 

Solution 6: (a) (i) and (iii)

In plants, sexual reproduction happens inside a plant, so choice (ii) is incorrect. Different agents such as wind, insects and animals bear pollinations, therefore alternative (iv) is incorrect.

Question 7:  Pollination refers to the

(a) transfer of pollen from the anther to the ovary.

(b) transfer of male gametes from the anther to stigma.

(c) transfer of pollen from the anther to stigma.

(d) transfer of pollen from the anther to the ovule. 

Solution 7: (c) transfer of pollen from the anther to stigma.

The transfer from the anther to the stigma of pollen grains is referred to as pollination. Pollen grains are immobile, they do not travel to meet the stigma by themselves. For this, an external agent is needed, such as wind and insects.

Very Short Answer Questions................

Question 8:  Fungus, moss and fern reproduce by a common method of asexual reproduction. Name the method. 

Solution 8:   By spore formation Fungus, moss and fern are reproduced.

Question 9:   Pick the odd one out from the following on the basis of mode of reproduction and give reason for it. 

Solution 9:    While the other three plants do, rice does not replicate by vegetative propagation. Therefore, the strange one is rice.

Question 10:  Boojho had the following parts of a rose plant – a leaf, roots, a branch, a flower, a bud and pollen grains. Which of them can be used to grow a new rose plant? 

Solution 10:   To grow a new rose plant, a branch may be used to.

Question 11:  Which type of pollination does Figure 12.1 indicate?

Solution 11:  Figure 12.1 indicates Self-pollination.

Question 12:  One morning as Paheli strolled in her garden she noticed many small plants which were not there a week ago. She wondered where they had come from as nobody had planted them there. Explain the reason for the growth of these plants. 

Solution 12:   It is likely that the seeds from the tree dropped below and germinated into small plants. Agents such as a breeze that germinated and grew into tiny plants may have taken the seeds to the greenhouse.      

Short Answer Questions......................

Question 13:  In the diagram given in Figure 12.2 label the parts marked (a), (b) and (c).

Solution 13:

Question 14: When you keep food items like bread and fruits outside for a long time especially during the rainy season, you will observe a cottony growth on them.

(a) What is this growth called?

(b) How does growth take place? 

Solution 14:

a) The growth is called fungus.

b) From the spores, bread mould emerges.

Question 15:  Group the seeds given in Figure12.3 (i) to (iii) according to their means of dispersion.

(a) Seed dispersed by wind

(b) Seed dispersed by water

(c) Seed dispersed by animal 

Solution 15:

i) and ii) are dispersed by wind;

iii) is dispersed by an animal.

Question 16:  Coconut is a large and heavy fruit. How is it adapted for dispersal by water? 

Solution 16:   On its surface, coco fruit has spongy fibers that make it float in water.

Long Answer Questions..............

Question 17:  In the figure of a flower given in Figure 12.4, label the parts whose functions are given below and give their names.

(a) The part which contains pollen grains.

(b) The part where the female gamete is formed.

(c) The female reproductive part where pollen grains germinate.

(d) The colourful part of the flower which attracts insects. 

Solution 17:

(a) The part which contains pollen grains: Anther

(b) The part where the female gamete is formed: Ovary

(c) The female reproductive part where pollen grains germinate: Stigma

(d) The colourful part of the flower which attracts insects: Petals

Question 18:   Fill in the blanks with correct terms.

The male and female gametes fuse to form a _____(a)______ during the process of _____(b)______. This grows into an _____(c)______ which is enclosed within a seed. After fertilisation the ovules develop into _____(d)______ and the ovary develops into a _____(e)______ . 

Solution 18:  The male and female gametes fuse to form a (a) zygote during the process of (b) fertilization. This grows into an (c) embryo which is enclosed within a seed. After fertilisation, the ovules develop into (d) seed and the ovary develops into a (e) fruit.

Question 19:  In the diagram of a bisexual flower given as Figure 12.5, draw the missing part and label the parts marked (a), (b) and (c). Also, label the missing part that you draw.

Solution 19:

Question 20:  Write how the following seeds are dispersed.

(a) Seeds with wings.

(b) Small and light seeds.

(c) Seeds with spines/hooks. 

Solution 20:

1. Winged seeds are spread by wind.
2. Wind disperses small and light seeds.
3. Animals spread seeds with spines/hooks.