Answer: The enzyme responsible for making sure that the correct RNA nitrogen bases are paired with the DNA strand is RNA polymerase.
Explanation: During transcription, RNA polymerase reads the DNA template strand and adds complementary RNA nucleotides to create the RNA molecule. The base pairing between DNA and RNA follows the rules of complementary base pairing, where adenine (A) pairs with uracil (U) and cytosine (C) pairs with guanine (G). The RNA polymerase ensures the correct base pairing by selecting the complementary RNA nucleotide that corresponds to the DNA nucleotide at each position along the template strand.