Scientists are often able to insert genes from the cells of one organism into * another so that the the gene is expressed in the recipient cell. For example, the gene for producing insulin in humans can be inserted into bacteria so that they produce insulin to treat diabetic patients. Which of the following explains why this is possible?

A.) All organisms use DNA replication to produce proteins

B.) All organisms use mRNA to direct the synthesis of codons.

C.) All living organisms use the same 4 letters to code for amino acids.

D.) All living organisms use the same proteins to regulate chemical reactions.