ecological succession vs environmental science

ecological succession and environmental science both are nouns.

Word	Noun	Adjective	Verb	Adverb
ecological succession	Yes	No	No	No
environmental science	Yes	No	No	No

ecological succession (noun)	environmental science (noun)
(ecology) the gradual and orderly process of change in an ecosystem brought about by the progressive replacement of one community by another until a stable climax is established	the branch of biology concerned with the relations between organisms and their environment