Which of these factors does not govern the stability of a conformation in acyclic compounds?

Statement $I$: Staggered conformation of ethane is more stable than the eclipsed conformation.
Statement $II$: The torsional strain in staggered conformation is more than in the eclipsed conformation.

The two structures $I$ and $II$ represent:

The incorrect statement regarding conformations of ethane is:

Which of the following conformations of $n$-butane is the most stable?

Different conformations of the same molecule are called