Identify the term that describes when a performer extracts a small portion of pre-recorded music and then mechanically repeats it over and over as a musical backdrop to the text of a song. this technique often occurs in rap music.

it is called "sampling"

Explanation:

In music, sampling is the recycle of a portion or sample of a sound recording in another recording. Samples may hold rhythm, melody, speech, or other sounds. They are usually integrated using hardware (samplers) or software such as digital audio workstations. Sampling without permission can break  copyright laws.

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