Multiple choice mRNA is built by adding ? Complimentary DNA nucleotides Complimentary tRNA Complimentary rRNA Complimentary RNA nucleotides Reveal answer Fill a bubble to check yourself D Correct answer Explanation Messenger RNA (mRNA) is a polymer of RNA nucleotides. During transcription, RNA polymerase links complementary RNA nucleotides (A, U, C, G) together based on the DNA template.