Question

A scientist is studying the action of RNA polymerase during transcription. He wants to know what type of bases are added to the growing mRNA by RNA polymerase.

Answer 1

The answer is A. RNA polymerase will be making an mRNA using a single DNA strand as a template. So, for example if the DNA strand is AGGCAGC the mRNA strand will be UCCGUCG. U= uracil which replaces thymine in mRNA molecules.
i hope my answer helped!!!!!!!