Monday, February 7, 2022

SCIENCE Ch.11 Reproduction in plants WORKBOOK QUES - ANS

 Ch.11 Reproduction in plants 

1. Name the following:(R) 

(a) The method of asexual reproduction in Spirogya.  

ans.: Fragmentation  

(b) An example of a rhizome. 

ans.: ginger/canna/turmeric. 

(c) Sepals of a flower collectively form this part.  

ans.: Calyx 

2. State whether the following statements are true or false. Correct the false  statements. (An) 

(a) The swollen structure present at the bottom of the style is called ovule.  ans.: False 

The swollen structure present at the bottom of the style is called ovary.  (b) A flower which bears all the four whorls is called a complete flower. ans.: True 

(c) In Vallisneria, pollination takes place through wind. 

ans.: False 

In Vallisneria, pollination takes place throughwater. 

(d) Pine trees produce reproductive structures called cones. 

ans.: True 

3. Assertion-Reason type questions:(An) 

In the following questions, two statements are given- one labelled Assertion (A)  and the other labelled Reason (R). Read the statements carefully and choose the  correct alternative (A), (B), (C) and (D) as given below. 

(A) Both A and R are true and R is the correct explanation of the assertion. (B) Both A and R are true but R is not the correct explanation of the assertion. (C) A is true but R is false. 

(D) A is false but R is true. 

(i) Assertion:Air currents carry dandelion seeds away from the parent plant. Reason: Dandelion seeds are light in weight. 

ans:(A) Both A and R are true and R is the correct explanation of the  assertion.

(ii) Assertion:Rubber trees are grown artificially. 

Reason:Rubber trees have rhizomes which grow by vegetative propagation. ans: (C) A is true but R is false. 

4. Explain the following terms. (R) 

(a) Runners 

ans: The horizontally growing stems are called runners. 

(b) Artificial propagation 

ans: Growing plants through artificial methods is known as artificial  propagation. 

5. Give reasons for the following. (An) 

(a) Seeds of burdock have hook-like structures on them.  

ans: The hook-like structures help the seeds to attach to the fur of animals. (b) Gulmohar is a bisexual flower. 

ans: Gulmohar flower contains both male and female flowers. Hence it is a bisexual flower. 

6. A field trip was organized for students of grade 7 to ICAR (Indian Council of  Agricultural Research). Students were shown the following picture on a method  used to develop new varieties of apples. Write the steps that are used to get  new varieties of apples by this method.(Ap)


In this method, a plant which is fast growing and resistant to diseases is  taken as the base ofthe plant. 

It is called the stock. 

To get the combined features of two plants, the stem of a healthy plant is  obliquely cut (graft or scion) and inserted over the stem of the stock  through a small incision. 

The stock and the scion are firmly bound together with a string. In a few weeks, the tissues of the stock and the scion fuse together. 

The stock provides the root system and supports the lower part of the new  plant. 

The upper part of the graft plant grows upwards and provides the stem, flowers  and fruits.

7. Observe the picture and answer the questions that follow.(Ap) 

(a) What does the picture depict? 

ans: The picture depicts the life cycle of a fern. 

(b) Name the structure that produces the egg. 

ans: The structure that produces the egg is called archegonium. 

(c) Name the structure formed by the germination of spores.  

ans: The spores develop into young gametophytes.

8. Place a potato having buds in a tray. Occasionally sprinkle few drops of water  on the buds. Observe the potato after a week and draw its picture.What  conclusion can be drawn from this activity?(Ap) 

Observation: 

Conclusion: Potato shows vegetative propagation through its stem/tuber

9. Given below are six bees roaming in an orchard. Follow the given lines to identify  the flowers on which each bee will sit. Draw or stick colourful pictures of the  flowers in the empty boxes. Write any 3 characteristics of insect-pollinated flowers in the table given below. (U)


ans: 

Bee 

Flower 

Characteristics of  

insect-pollinated  

flowers. 

1) Flowers are brightly  coloured 

2) Flowers have  

fragrance 

3) Flowers have lots of  nectar

Bee 1 

Sunflower

Bee 2 

Poppy

Bee 3 

Lillies

Bee 4 

Lavender

Bee 5 

Allium

Bee 6 

Rosemary



Give three more examples of insect-pollinated plants.  

Apple, mango, beet, onion are other examples of plants which are pollinated by  bees. 

(answers may vary accept all correct examples) 

10.Higher Order Thinking Skills (HOTS) (U) What will happen if a potato plant with undesirable characteristics reproduces  asexually? 

ans: The offsprings of the potato plant will also have undesirable  characteristicsduring asexual reproduction, the parent plants give rise to  identical offsprings.


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