Name the source from which nitrogen and oxygen are obtained on a large scale.

Q. Name any one green house gas and its possible source of production on a large scale. What are the harmful effects of it?

Q. Iron is obtained on a large scale from $F{e}_2{O}_3$ by

Q. The raw materials obtained from primary activities are converted into finished products through machinery on a large scale. These activities are called ________.

Q. Name the source from which the following are obtained:

(a) silk
(b) wool
(c) angora