yes, it is.
Yes,an empty set is the subset of every set. The subset of an empty set is only an empty set itself.
yes.
Yes it is. Everything in the empty set (which is nothing of course) is also in the empty set. If it's not in the empty set, it's not in the empty set. The empty set has no propersubsets, though, or subsets that are different from it.
yes
Yes, it is
Yes
Yes, empty set means null which is no solution.
Yes
yes
yes, they can eat fruit.
yes, if the set being described is empty, we can talk about proper and improper subsets. there are no proper subsets of the empty set. the only subset of the empty set is the empty set itself. to be a proper subset, the subset must be strictly contained. so the empty set is an improper subset of itself, but it is a proper subset of every other set.