Reason : These organisms shift to sexual mode
of reproduction just before the onset of adverse
conditions.
- Assertion : In oviparous animals, the fertilized eggs
are covered by hard calcareous shell and laid in a safe
environment.
Reason : Chances of survival of embryo are greater
in oviparous animals, as compared to viviparous
animals.
- Assertion : In majority of sexually reproducing
organisms, the gametes produced are morphologically,
of two distinct types.
Reason : They are called heterogametes, and refer to
antherozoid and ovum.
- Assertion : The first menstruation begins at puberty
and is called menarche.
Reason : The cycle of events starting from one
ovulation till the next one is called menstrual cycle.
- Assertion : Annual and biennial plants show clear
cut vegetative, reproductive and senescent phases.
Reason : All annual and biennial plants are
monocarpic.
- Assertion : Clones are morphologically and genetically
similar individuals.
Reason : Clones are common in single-celled
organisms, and in plants and animals with relatively
simple organisation.
Figure Based Questions- Refer to the given figure showing different techniques
of vegetative propagation. Identify these techniques
labelled as A, B, C, D, E and F.
40. Fill in the given blanks using letters assigned to
different techniques in previous question. You may
use appropriate phrases, where required.
(a) Oblique sloping cut or notch in (i) is given to
both stock and scion, so they fit into each other.
(b) (ii) is used to obtain virus free plants and
homozygous diploids.
(c) V shaped notch is given to stock in (iii), while
wedge like cut is given to scion.
(d) The stock has a larger diameter than scion in (iv),
and many scions are inserted in the slits.
(e) (v) is an ancient technique of propagation in
tropical trees and shrubs, generally done in early
monsoon rain.
(f) In (vi) , two independently growing plants are
brought together, and their shoots are given cuts
at the same level, for a distance of 2.5-5.0 cm.
chApTer-2 : seXUAL reprODUcTIOn
In FLOWerInG pLAnTs
multiple choice Questions- Select the correct order of endosperm types.
(a) A-Cellular, B-helobial, C-free nuclear
(b) A-Cellular, B-free nuclear, C-helobial
(c) A-Helobial, B-free nuclear, C-cellular
(d) A-Free nuclear, B-cellular, C-helobial- Given figures represent different stages of embryo sac
development in angiosperms (I-VIII). Arrange them in
correct order and select the correct option.