Films are often divided into genres, which describe the typical subject matter -- what the film is about. This is distinct from film styles, which describes filmic conventions which can be applied to any genre. Of course, the more that genres are defined, the more likely that a filmmaker will try to combine, transcend and evade categories, so not every film can be neatly labeled.
... needs and oxygen as a waste product that is released into the environment.
In green plants and algae, the pigment molecules that initially absorb the light energy are ...