1) the superlative degree is shown in adjectives by the

a. -er
b. -ed
c. -est
d. -ing

2) attentiveness is

a. a courtesy
b. a combining form
c. a type of critical thinking
d. a type of grammatical meaning

  1)  c. -est

  2) a. a courtesy

Step-by-step explanation:

1) The words "greatest" and "smallest" give you a clue that superlative adjectives end in -est.

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2) Paying attention (attentiveness) is a discipline of behavior, not a description of English syntax or grammar. It is best when accompanied by an attitude of acceptance and a desire for understanding, rather than critical thinking.

Attentiveness is a courtesy.

answer: c is correct, a regular pentagon