The theme of a story is the A. main character.

B message about life that the author expresses.

C the sequence of events.

D short summary of what the story is about.

the answer is B message about life that the author expresses.

comfortable

explanation:

one type of the adjectives is predicate adjective. a predicate adjective is an adjective which follows a linking verb and modifies or refers back to the main subject of that linking verb.

it usually is used just before the noun it modies.

here in this example:

'penguins seem comfortable in the coolest habitats', comfortable is the predicate adjective which follows the linking verb 'seem' and modifies the noun.