19. The scientist used in her experiment.

Nitrogen (capitalized)
nitrogen (not capitalized)

answer; ///(a)//the death of his

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.

the meaning of the phrase fnch clear means it is understandable and readable.