91. The number of chromosomes in Down’s syndrome is
A. 46
B. 47
C. 48
D. 45
92. The most abundant tissues of our body are
A. Muscular
B. Connective
C. Epithelial
D. Nervous
93. Most fish do not sink in water because of the presence of
(i) swim bladder
(ii) air bladder
(iii) air sacs
(iv) air in spongy bones
A. (i) and (ii) are correct
B. (ii) and (iii) are correct
C. (iii) and (iv) are correct
D. (i), (ii), (iii) and (iv) are correct
94. Ozone hole refers to
A. hole in the ozone layer
B. a decrease in the ozone layer in the troposphere
C. a decrease in the thickness of the ozone layer in the stratosphere
D. increase in the thickness of the ozone layer in the troposphere
95. Atoms are composed of
A. electrons and protons
B. electrons only
C. protons only
D. electrons and nuclei