71 What are hormones?
Secretions of ductless glands
72 The velocity of radio waves is same as that of
Elastic waves
73 In Rutherford atomic model, the path of electrons will be
Circular
74 The Salvia in the mouth acts upon
Starch
75 Gene is
An elementary unit of heredity
76 A blood vessel that carry deoxygenated blood is the
Pulmonary artery
77 The best source of vitamins for a high school pupil is
A properly varied diet
78 The science for the study of old age is known as
Gerontology
79 The instrument used to detect the radiation just outside the red end of the visible spectrum is
Thermopile
80 The most destructive enemy of forests is
Fire
