Their are 9 characteristics:
having respiration(exchange of gasses)
metabolism (The breaking down of substance and convert to energy
Has two kinds:anabolism(to construct components of a cell) & catabolism(breaks down organic matter)
Reaction(to counter an/a event/phenomena)
has homeostasis(maintain a system stable)
high degree of organization (this causes their outward appearance,different than the previous characteristic,i assure you)
Identity
grow and develop at some point in their lives
create/reproduce organisms similar to themselves
Also has two kinds:Asexual & Sexual Reproduction
communicate with organisms similar to themselves
move under their own power.