How does the diction affect the imagery in the poem? The adjective “comfortable” helps the reader “see” the fish. The verb “splashing” helps the reader “touch” the pond. The noun “pond” helps the reader “taste” the fish. The noun “rippulous” helps the reader “hear” the pond.

The noun 'rippulous' helps the reader 'hear' the pond.

Explanation:

The Lorax is a children's fiction witten by Dr. Seuss. The book speaks about the plight of our environment.

The imagery is a literary device used by the writer to appeal to the sense of sight of the readers. Through the lens of thsi rhetoric, the readers are able to see what the narrator sees.

So, the diction that affects the imagery is the word 'rippulous' helps the reader to 'hear' the pond. The word 'rippulous' appeals to the sense of sight of the readers, and enables  them to hear the sound that ripples make in a pond.

Thus the last option is the correct answer.