How many conformations of alkane are present? Why?

(N/A) Alkanes can have an infinite number of conformations due to rotation around $C-C$ single bonds.
Reason: $A$ sigma bond is present between two carbon atoms in an alkane.
The electron distribution of the sigma molecular orbital is symmetrical around the internuclear axis of the $C-C$ bond,which is not disturbed by rotation about its axis.
This rotation results in different spatial arrangements of atoms,which can interconvert into one another.