Final answer:
The underlined words in the passage give it a positive tone by using pleasant descriptive words that convey tranquility and wonder.
Step-by-step explanation:
The underlined words in the passage from Through the Looking-Glass by Lewis Carroll contribute to a positive tone. Descriptive words such as "drift," "gently," "waves," "carefully," "plunged," "tangled," "bright," "eager," and "darling scented" convey a sense of tranquility, curiosity, and appreciation for the natural beauty experienced by the protagonist, Alice. The use of pleasant adjectives and the character's interaction with her environment create an atmosphere of wonder and positivity.