What are genes? A. A whole DNA molecule that codes for many proteins

B. Section of DNA that code for a DNA molecule

C. Sections of DNA that code for a protein

A. A whole DNA molecule that codes for many proteins

Explanation:

To carry out these functions, DNA sequences must be converted into messages that can be used to produce proteins, which are the complex molecules that do most of the work in our bodies. Each DNA sequence that contains instructions to make a protein is known as a gene.

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:

answer; polycythemia is the correct answer;