Gonna need a bit more information then that if you want an answer.
Concept of the role<span> of the genetic code (e.g., </span>mRNA<span> bases determine the sequence of ... for a detailed explanation—examples of acceptable </span>answers<span> include, but are not.</span>
Answer:
four types of nitrogen bases od DNA nucleotides are; Thymine, Adanine, guanine and cytosine