them. Fertilisation is internal external and they are mostly
viviparous oviparous.- (a) 20. (c) 21. (c) 22. (d) 23. (c)
- (c) 25. (a) 26. (b) 27. (a) 28. (a)
- (a) Presence of a single functional ovary on the left side in
the female birds and absence of urinary bladder.
(b) Only the left ovary and oviduct are developed in the mature
females. Birds do not have the urinary bladder, which is
present to store the urine temporarily in other animals.
Moreover, the water of the excretory fluid is reabsorbed in
the urinary tubules of kidneys and in the cloaca. The result
is the formation of a semisolid excreta, chiefly containing
the insoluble uric acid and urates which are excreted at
once. These features help in reducing the unnecessary
weight of the body which are advantageous for their flight.
(c) Fertilisation takes place in the oviduct, near the ovary.
(d) The shell gland which is actually the wall of oviduct,
secretes albumen, shell membranes and calcareous shell
over the egg. When the egg is laid, the shell on coming in
contact with air becomes hard and non-porous which is
essential for the proper development of the embryo. So, if
the shell gland is non-functional, the egg will get broken
easily and the young one would not develop.- (a) In the given figure, A isTaenia, B is Aurelia and C is Octopus.
(b) Organism A (Taenia) shows parasitic mode of nutrition.
Its body is divisible into scolex, neck and strobila. Scolex
contains cone like rostellum at its top. Rostellum bears
chitinous hooks in two circlets. On the middle part of scolex,
4 cup shaped suckers are present. Hooks and suckers are
adhesive organs which help these parasites to attach firmly
to the body of host from which they derive nutrition. Hence,
these structures supplement their parasitic mode of nutrition.
(c) The epidermis of organism B consists of the following
cells. (i) Epitheliomuscular cells that provide protection
and act as muscles. (ii) Cnidoblasts ( = stinging cells) has
nematocyst (‘stinging organ’) which are used for defence
and offence. (iii) Interstitial cells are reserve cells also
called totipotent cells which can be converted into any type
of cells. (iv) Nerve cells form a primitive nervous system. (v)
Sensory cells are sensory in function.
(d) Organism C (Octopus) belongs to Phylum Mollusca. It
ejects inky fluid in water and forms a screen for defence
from its enemies.
Unscramble the words given in column I and match them with their explanations in column II.Column I Column II- NHOMECAUTRI (a) Integral carrier proteins that facilitate the transport of a given molecule
through a cell membrane. - ECILHN (b) Occasional reappearance of a remote ancestral trait in some individuals
of a species. - SOONKLIGYEI (c) Mutant organism that cannot grow in the minimal medium and require
additional nutrients. - SLCHOISIE (d) A synthetic teratogenic drug that is used in treatment of multiple myeloma.
- SIVAMTA (e) Pioneer species in xerarch succession.
- NAECCLUR (f) Inflammation of kidney, typically due to a bacterial infection.
- ESRMSAEPE (g) Genetic material which shows maximum staining during metaphase and
less staining in interphase nucleus. - OOUHATXRP (h) The scientific study of body movements.
- IHOATDEIDML (i) A condition characterised by dry scaling, fissuring of the lips and
corners of the mouth due to riboflavin deficiency. - HEOPYRILTSIPEN (j) An outgrowth or appendage at or near the hilum of castor seed.
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