Answer:
Grammatical name- Adjectival clause.
Function- Qualifying the noun 'the atmosphere.'
Explanation:
An adjectival clause can be defined as a dependent clause which consists of a subject and a verb, yet does not comprehend complete meaning. An adjectival clause starts wih relative pronoun that, where, when, etc. An adjectival clause serves as an adjective in a sentence.
In the given sentence, the pharse 'that now prevails' serves as an adjectival clause. The phrase is describing and qualifying the noun 'the atmosphere.' The phrase is comprehending the noun, 'the atmosphere', which was present at the moment.
Therefore, correct answers are:
Grammatical name- Adjectival clause.
Function- Qualifying the noun 'the atmosphere.'