Things that modify nouns are prototypically adjectives or equivalent to adjectives.

I beg to modify your proposal.

When you read my sentence and suggest that I modify just one word (for example, "cat" or "dog"), it makes me happy, because that means that the sentence is practically correct.

Things that modify nouns (adjective, or adjectival equivalent).

What do adjectives modify?

You'll have to modify the height of the table to make it fit.

Terraformers wanted to modify the Venusian atmosphere so that some day it might support life.

We want to modify the regulations of our school.

What do adverbs modify?

Algerians need to modify their behavior to preserve their environment.