Why is the average number of fish species not a whole number?

The answer is a fish because I know that

There is one s orbital, and there are three p orbitals, five d orbitals, and seven f orbitals. thus, the answer is b. do not confuse the number of orbitals in a subshell with the number of electrons the subshell can hold. each orbital can hold two electrons, so the capacity of an nf subshell is 14 electrons.

You know how the first one if filled up like the objects do the same but with the other categories