Answer:
A. A pairs with U
Explanation:
In DNA, the nitrogenous bases are A, T, G, and C. In RNA, the nitrogenous bases are A, U, G, and C.
A pairs with U in RNA because it requires less energy to use uracil over thymine.
Hope that helps.
Answer: Transcription
Explanation: Genes consist of sequences of molecules, called bases, in your DNA. During transcription, an enzyme called RNA polymerase “reads” your genes and copies the information onto molecules of messenger RNA.
Not sure what you are asking :)