Which of the following items is not composed of matter?
a. dirt
b. humans
c. sound
d. water

c. sound

Explanation:

Matter is formally defined as being any substance that has any amount of mass and takes up space by having volume. Dirt, Humans, and Water all have a different level of mass and take up a different level of space. Sound on the other hand does not have neither mass or volume, it is instead a wavelength or a constant vibration that travels invisibly through the air. Therefore it is not composed of matter.

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regulation of gene expression. gene expression can be regulated by various cellular processes with the aim to control the amount and nature of the expressed genes. these regulatory proteins bind to dna and send signals that indirectly control the rate of gene expression

explanation: