If you wanted to prevent a regulatory protein from changing gene expression, you would have to prevent physical contact between the protein and .

DNA

Explanation:

Regulatory proteins can prevent and activate gene expression based on their binding with DNA sequences under specific conditions. If the ability of regulatory protein to bind with DNA sequence is altered, they do not express genes. For example, Lac I is a regulatory protein which when binds to DNA and prevents gene expression. This happens because of absence of signal molecule and when this signal molecule is present, the Lac I bind with it and releases thereby expressing the gene.

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i guess you forgot putting it.

when the displaced particles are perpendicular to the direction the wave travels, is called a transverse wave, whereas in longitudinal wave the displace practices are parallel to the direction of the wave.

in the given image:

first image shows - longitudinal wave

second image shows - transverse wave

third image shows - longitudinal wave

fourth image shows - longitudinal wave