How does the narrator of "the tell-tale heart" kill the old man?
a. he scares him to death.
b. he cuts his heart out.
c. he stabs him.
d. he suffocates him under the bed.

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.