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Question Answers

Q.1 Boojho wants to know if there is any advantage of vegetative propagation. (page 135)
Ans. Plants produced by vegetative propagation take less time to grow and bear flowers and fruits earlier than those produced from seeds. The new plants are exact copies of the parent plant, as they are produced from a single parent.
Q.2 Boojho wants to know how the male gamete in the pollen grain reaches the female gamete present in the ovule. (Page 137)00
Ans. A pollen grain on the stigma grows in a tiny tube, all the way down the style to the ovary. This pollen tube carries a male gamate to meet a female gamate in an ovule.
Q.3 Boojho wants to know why flowers are generally so colourful and fragrant. Is it to attract insects ? (Page 138)
Ans. Flowers are so colourful and fragrant to attract insects which help in the process of pollination.
NCERT TEXTBOOK EXERCISE         (Page 141 – 142)
Q.1 Fill in the blanks:
(a) Production of new individuals from the vegetative part of parent is called…………
(b) A flower may have either male or female reproductive parts. Such a flower is called……..
(c) The transfer of pollen grains from the another to the stigma of the same or of another flower of the same kind is known as………..
(d) The fusion of male and female gametes is termed as……..
(e) Seed dispersal takes place by means of………, ………. and………
Ans. (a) vegetative propagation; (b) unisexual flowers; (c) pollination; (d) fertilisation; (e)wind insects, water.
Q.2 Describe the different methods of asexual reproduction. Give examples.
Ans. The various methods of asexual reproduction are:
(i) Vegetative propagation, for example stem cutting of rose or Champa.
(ii) Budding, for example reproduction in yeast by budding.
(iii) Fragmentation, for example Fragmentation in spirogyra. 
(iv) Spore formation, for example reproduction in fern.
Q.3 Explain what you understand by sexual reproduction?
Ans. In this type of reproduction male gamete (sperm) combines with the female gamete(ovum) in animals to form zygote.
Q.4 State the main difference between asexual and sexual reproduction.
Ans. Sexual Reproduction
(i) It occurs both in lower and the higher organisms but mostly in higher plants and animals.
(ii) In it, there is fusion of two (male and female) gametes and for this the sex is required. 
(iii) The new individual formed is identical to the parent.
Asexual Reproduction
(i) Usually occurs in lower organisms. 
(ii) Only one parent is sufficient in a sexual reproduction.
(iii) The new individual formed is similar but not identical to the parents.
Q.5 sketch the reproductive parts of a flower.
Reproductive parts of flower
Fig. Reproductive parts of a flower.
Q.6 Explain the difference between self-pollination and cross pollination. 
Ans. The transfer of pollen from the another to the stigma of a flower is called pollination. If the pollen lands on the stigma of the same flower, it is called self- pollination. When the Pollen of a flower lands on the stigma of another flower of the same plant, or that of a different plant of the same kind, it is called cross- pollination.[Fig (a)and (b)].
Fig. Pollination in flowers.
Q.7 How does the process of fertilisation take place in flowers? 
Ans. Fertilisation is the process in which male and female gametes fuse together. In flowering plants the Pollen fuses with ovules present in the ovary to form a zygote, which later on develops into seed.
     Fig. Fertilisation (zygote formation) in flowers.
Q.8 Describe the various ways by which seeds are dispersed.
Ans. In nature same kind of plants grow at different places. This happens because seeds are dispersed to different places. Sometimes, after a walk through a forest or a field or a park, we may have found seeds or fruits sticking to our clothes. 
Seeds and fruits of plants are carried away by wind, water and animals. Winged seeds such as those of drumstick and maple [fig. (a) and (b)], light seeds of grasses or hairy seeds of aak (Madar) and hairy fruit of sunflower [Fig. (a),(b)], get blown off with the wind to far away places. Some seeds are dispersed by water. These fruits or seeds usually develope floating ability in the form of spongy or fibrous outer coat as in coconut. Some seeds are dispersed by animals, especially spiny seeds with hooks which get attached to the bodies of animals and are carried to distant places. Examples are: Xanthium (Fig.) and Urena.
Fig. Seeds of
(a) drumstick and 
(b) Maple. 
Fig. (a) The hairy fruit of sunflower and 
        (b) hairy seed of Madar (aak).
some seeds are dispersed when the fruits burst with sudden jerks. The seeds are scattered far from the parent plant. This happens in the case of castor and balsam.
               Fig. Xanthium
Q.9 Match items in column I with those in column II
Column IColumn II
(a) Bud(i) Maple
(b) eyes(ii) Spirogyra
(c) Fragmentation(iii) Yeast
(d) Wings(iv) Bread mould
(e) Spores(v) Potato
 (vi) Rose
Ans. (a) (iii); b (v); (c) (ii); (d) (i); (e) (iv).
Q.10  Tick (✓) the correct answer.  
(a) The reproductive part of a plant is the:
(a) leaf (b) stem (c) root (d) flower. 
(b) The process of fusion of the male and the female gametes is called :  
(a) fertilisation (b) pollination (c) reproduction (d) seed formation. 
(c) Mature ovary forms the: 
(a) seed (b) stamen (c) pistil (d) fruit. 
(d) A spore producing plant is: 
(a) Rose (b) bread mould (c) potato (d) Ginger. 
(e) Bryophyllum can reproduce by its :
(a) stem (b) leaves (c) roots (d) flower.
Ans. (a) (iv); (b) (i); (c) (iv); (d) (iii); (e) (ii).

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