Q21 of 60 Page 1

(a) Name the parts labelled as A, B, C and D in the diagram given below:


(b) What is pollination? State its significance.


(b) How does fertilization occur in flowers? Name the parts of the flower that develop into (i) seed, and (ii) fruit after fertilization.


(a) The diagram along with the labeled parts are as follows:



(b) Pollination: It is a type of asexual reproduction in which the pollen grains are transferred from the anther of a stamen to stigma of a carpel. Pollination is of two types:


(a) self-pollination


(b) cross pollination


Pollination is significant as it is the reason which causes variation in the plant species.


(c) Stigma receives the pollen grains from anther of stamen during the process of pollination. When a pollen falls on Stigma, it bursts open and grows a pollen tube downward through style towards female gamete in ovary. A male gamete moves down the pollen tube. The female gamete also known as Ovum combines with the male gamete to form zygote. The zygote formed thus develops into a plant.


(d) Ovary is developed into a fruit and eggs present in the ovule gets fertilized by pollen grain and develops into fruit.


More from this chapter

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19

Elements forming ionic compounds attain noble gas configuration by either gaining or iosing electrons from their outermost shells. Give reason to explain why carbon cannot attain noble gas configuration in this manner to form its compounds. Name the type of bonds formed in ionic compounds and in the compounds formed by carbon. Also give reason why carbon compounds are generally poor conductors of electricity.

 20

(a) Draw a sectional view of human female reproductive system and label the part where

(i) eggs develop.


(ii) fertilisation take place.


(iii) fertilised egg gets implanted....


(b) Describe, in brief, the •changes the uterus undergoes


(i) to receive the zygote.


(ii) if zygote is not formed.

 22

Explain the following terms related to spherical lenses:

(i) optical center


(ii) centers of curvature


(iii) principal axis


(iv) aperture


(v) principal focus


(vi) focal length


(b) A converging lens has focal length of 12 cm. Calculate at what distance should the object be placed from the lens so that it forms an image at 48 cm on the other side of the lens.

 23

(a) List the parts of the human eye into it. Explain how they perform this function.

(b) Write the function of retina in human eye.


(c) Do you know that the corneal-impairment can be cured by replacing the defective cornea with the cornea of the donated eyes? How and why should we organize groups to motivate the community members to donate their eyes after death?