11. The gas accidentally released by Union Carbide pesticide plant (Bhopal gas tragedy) in 1984 was
Methane
Methyl isocyanate
Sulphur dioxide
Carbon monoxide
12. Diamond is a form of
Nitrogen
Oxygen
Hydrogen
Carbon
13. The water that does not produce good lather with soap is called
Heavy water
Soft water
Hard water
Polluted water
14. The age of a tree can be determined by
Measuring its diameter
Measuring its height
Analyzing its sap
Counting the annual growth rings of its stem
15. The chemical substance present in bones and teeth is
Calcium phosphate
Calcium borate
Calcium sulphate
Calcium chloride