The chemical industry is a very important contributor to the wealth of a country. For example it contributes over 1% to the Gross National Product (GNP) of European countries, which is over 6% of the total GNP produced by all manufacturing industries.
The answer is the elements in a periodic table. <span>On the basis of the elements in the periodic table, they are divided into metals and non metals. </span>
Drill cores from the ocean floor were dated and found to be very young compared to the age of the earth. This means the crust had to be formed recently, which can be explained by creation of crust at a spreading center.