1. Which of the following is necessary for burning (combustion)?   Nitrogen   Petrol   Oxygen   Carbon   Hint Half-n-half Clue   2. Which gas in the atmosphere protects us from harmful ultraviolet radiations?   Carbon Dioxide   Ozone   Nitrogen   Oxygen   Half-n-half Clue   3. The Sun is a   Star   Comet   Satellite   Huge Planet   Half-n-half Clue   4. Which gas evolves when charcoal is burnt?   Nitrogen   Carbon Dioxide   Oxygen   Ozone   Half-n-half Clue   5. Who discovered the circulation of blood?   William Harvey   Louis Pasteur   Hargobind Khorana   Edward Jenner   Half-n-half Clue   6. Which planet is known as the Red Planet?   Jupiter   Mars   Earth   Mercury   Half-n-half Clue   7. A communicable disease can be passed on from one person to another.   True   False