My heart _fell_ when I realized we were moving away.

a.

adverb

c.

verb

b.

noun

d.

adjective

Your answer is D adjective because adjectives are used to describe that in this sentence your use I it when his heart fell when he found out he was moving your were describing that he didn't want to move besides its not C because verbs are used to describe an action so that's not it its not A because adverbs use to tell the time of something like the setting and when it came down to B, and D I choose D.

Your answer is D.

C. verb

It is an action.