The Brainliest Answer!
(A)Food chain is a chain of food of animal and human being or it is a sequences.

(B)biotic factors are those which are obtain from environment and are livings.For examples flora and fauna.

(C)abiotic factors are those factors which are not obtAIN from environment and are non living.For examples=metals and non meTals etc

(D).Ecosystem is a place in which a organism live very comfortablily and easily acheives its requirements.
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