Which of the following phrases best defines rhythm?

Repeated sounds across lines of poetry
a poem's cadence, pace, or ongoing momentum
A collection of lines in a poem
The regular of irregular rhyme scheme in a poem

a poem's cadence, pace, or ongoing momentum

a poem using onomatopoeia 15 lines

To determine which of the given phrases best defines rhythm, we need to understand the concept of rhythm in poetry. Rhythm refers to the pattern of stressed and unstressed syllables in a line of poetry, creating a sense of musicality and movement. It creates a cadence, pace, or ongoing momentum within the poem.

Now let's evaluate the provided phrases:

1. "Repeated sounds across lines of poetry" - This phrase describes the concept of rhyme, which is not the sole defining characteristic of rhythm. While rhyme can contribute to the overall rhythmic quality of a poem, it does not capture the complete essence of rhythm.

2. "A poem's cadence, pace, or ongoing momentum" - This phrase encompasses the essence of rhythm. It recognizes that rhythm involves the flow and movement within a poem, including its cadence, pace, and ongoing momentum. Thus, this phrase is the most accurate definition of rhythm among the given options.

3. "A collection of lines in a poem" - This phrase may be referring to the overall structure or organization of a poem, but it does not specifically define rhythm.

4. "The regular or irregular rhyme scheme in a poem" - This phrase specifically refers to the pattern of end rhyme and does not capture the entirety of rhythm. While rhyme scheme can contribute to the rhythmic quality of a poem, it is not the sole characteristic that defines rhythm.

Based on this evaluation, it can be concluded that the phrase, "a poem's cadence, pace, or ongoing momentum," best defines rhythm.