____ are elements and compounds that occur naturally in the Earth crust.
The elements or compounds, which occur naturally in the earth's crust, are known as __________.
An inorganic compound (A) made of two most occuring elements into the earth crust, having a polymeric tetra-headral network structure. With carbon, compound (A) produces a poisonous gas (B) which is the most stable diatomic molecule. Compounds (A) and (B) will be