Final answer:
The phrase 'as sweet as sugar' is a simile, a form of figurative language that compares two different things to create a vivid image.
Step-by-step explanation:
The phrase 'as sweet as sugar' is an example of a simile, which is a figure of speech that compares two different things using the words 'like' or 'as'. Figurative language such as similes enrich the language by creating vivid images and connections between concepts. In this case, the comparison between the puppies' sweetness and sugar creates a clear, relatable image in the reader's mind. This use of figurative language adds depth and emotion to the text, making it more engaging and memorable.