How do carbon atoms form bonds in so many ways

How do you explain the ability of carbon atom to form one single bond and one triple bond?

The numbering of carbon atoms is done in such a way that the substituted carbon atoms have the lowest possible numbers

How many carbon atoms are present in one unit cell of diamond ?

In which allotrop of carbon does each atom form four bonds with other carbon atoms?

How do pi - bonds are formed ? How many pi - bonds are there in sp hydridisation ?

Why does carbon form compounds mainly by covalent bonding?

How does carbon fixation occur in biological form?

The carbon-carbon bonds in benzene are