Within a cell, the amount of protein made using a given mRNA molecule depends partly on

a. the degree of DNA methylation.

b. the rate at which the mRNA is degraded.

c. the number of introns present in the mRNA.

d. the types of ribosomes present in the cytoplasm.

b. the rate at which the mRNA is degraded.

Explanation:

DNA is transcribed into mRNA which then joins ribosomes present in the cytoplasm to serve as a template for protein synthesis. Regulation of gene expression occurs at several levels.

One such regulatory mechanism is the stability of mRNA and the rate of its degradation which in turn affects the availability of template for the process of protein synthesis and thereby keeps a check on the total amount of protein being formed in a cell.

For example, a very short life span of bacterial mRNA (few minutes) allows them to regulate the pattern of protein synthesis quickly in response to the changes in surroundings.