Explanation:
true for some cases (only some lines with the same slope lie on top of each other, others are parallel and completely separate).
not true in any case (if their slopes are different, they WILL intersect).
true for some cases (parallel lines that are not identical have different y-intercepts but never intersect each other).
true for all cases (the same slope but different y-intercepts means they are parallel and truly separate and are therefore never intersecting each other).