Answer:
The absence of rhymes.
Step-by-step explanation:
In literature theory, Free verses, also called irregular verses, are those that present an absence of rhymes and do not follow a defined metric pattern. That is, they do not obey the fixed forms, being, therefore, in opposition to the regular verses, which have the same measure.
The sonnet "Monet's Waterlilies" is a great example of free verses, since it does not present any pattern of rhymes.
It is important to note that the poetic texts that present the free verses do not fail to present the main characteristic of poetry: musicality.