Reasoning

Area, circumference, and quadrilateral are all terms used in the study of geometry. Variable is a term generally used in the study of algebra.

All except Whale lay eggs.

All except Acre are units of measuring distance, while acre is a unit of area.

All except Instruct denote learning process.

The noun, preposition, and adverb are classes of words that make up a sentence. Punctuation belongs in a sentence, but punctuation is not a class of word.