Plants like Elm (Ulmus), Dandelion (Taraxacum) and members of Rose Family vegetatively reproduce by
(1) Rhizome
(2) Sucker
(3) Stolon
(4) Corm
(2) Suckers, vegetative formation of a new stem and root system from an adventitious bud of a stem or root, either naturally or by human action.
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(2) Read page 7, XII NCERT
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Water hyacinth is one of the most invasive weeds primarily because:
(1) It gets adapted to any fresh water body easily
(2) It produces secondary metabolites against herbivores
(3) It can propagate vegetatively at a phenomenal rate
(4) It is predated upon by a large number of organisms
(3) Read page 8, XII NCERT
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(1) Read page 10, Figure 1.5, XII NCERT
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When both male and female flowers are present on the same plant, then plant is said to be:
(1) Bisexual
(2) Monoecious
(3) Unisexual
(4) Dioecious
(2) Read page 11, XII NCERT
The best answer is 2 because plants are monoecious or dioecious but flowers are unisexual or bisexual.
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(2) Read page 13, Table 1.1, XII, NCERT
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The most critical event in sexual reproduction is:
(1) Gametogenesis
(2) Gamete transfer
(3) Fertilization
(4) Embryogenesis
(3) Read page 14, XII NCERT
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With respect to organisms exhibiting internal fertilization, organisms exhibiting external fertilization show:
(1) More variations
(2) Great synchrony between sexes
(3) Large female size than males
(4) Less vulnerability to predation
(2) Read page 14, XII NCERT
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(1) Read page 7, Fig. 1.4, XII NCERT
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In animals exhibiting internal fertilization:
(1) There is high synchrony between the two sexes
(2) The chances of desiccation of the embryo is high
(3) The male gamete is motile
(4) Vulnerability to predators is increased
(3) Read page 15, XII NCERT
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