21 The ratio of the speed of sound in steel to its speed in air is
15 : 1
22 Anti-polio vaccine was discovered by
Jonas E. Salk
23 Exobiology is the study of
Life or its possibility on other planets
24 Anti-matter is
Anti-particles constituting nuclei of anti-protons and orbital positrons
25 The electric device that would transmit sound as well as image is called
Videophone
26 Typical vertebrates have tails but humans do not have one. What is the reason?
Man had a tail but it was lost during development
27 Weathering is
Decomposition of rocks
28 Larynx is also called
The Adam’s Apple
29 Anti-rabies treatment was evolved by
Louis Pasteur
30 Hydroponics is the art of
Growing plants without soil
