The correct response would be B: ability to move and eat, and are multi-cellular.
All animals share the characteristics of being multi-cellular organisms and having the ability to move (at least at some stage of their life cycle) and eat (they require energy and nutrients). Option A incorrectly states "single-celled," which does not apply to animals. Option C mentions the ability to fly, which is not a characteristic of all animals, and option D specifies standing on four legs, which is also not applicable to all animal species.