Which layer protects earth from harmful rays of the Sun?
A). Ionosphere
B). Ozone layer
C). Troposphere
D). Magnetosphere
1. The velocity of sound is more of
2. Which is the purest form of iron ?
4. Carbon, diamond and graphite are together called:
5. The major constituent of gobar gas is
7. Which of the following is used to denature ethanol ?
8. Which of the following is a flightless bird?