5. a. is double-stranded like dna b. has the same four nitrogen bases as dna c. contains ribose d. contains thymine 6. the pattern of base pairing in dna can be summarized by the rule a. purines always pair with purines b. any purine can pair with pyrimidine c. pyrimidines only pair with pyrimidines d. adenine pairs with thymine, and cytosine pairs with guanine 7. dna a. involves rna polymerase b. occurs at one site c. requires a dna molecule to start the process d. needs several days' time to occur 8. transporting amino acids to ribosomes for assembly into needed proteins is the function a. dna b. mrna c. rrna d. trna 9. transcription a. at ribosomes b. in the cytoplasm of the cell c. in the nucleus of the cell d. as the last step in protein synthesis

Option C is correct.

c. contains ribose.

RNA stands for ribonucleic acid. It is an important molecule with long chains of nucleotides. A nucleotide contains a nitrogenous base, a ribose sugar, and a phosphate. It is single stranded and it contains uracil base that is not present in DNA.

option D is correct.

d. adenine pairs with thymine, and cytosine pairs with guanine

In DNA purines always make bond with pyrimidine and pyrimidine make bond with purines, so there are double bond between adenine and thymine and triple bond between cytosine and guanine.

Option A is correct.

a. involves RNA polymerase

DNA polymerase is a vital enzyme in DNA replication. DNA polymerase is an enzyme that synthesizes DNA molecules from deoxyribonucleotides, the building blocks of DNA.

Option D is correct.

d. tRNA

The job of tRNA is to read the message of nucleic acids, or nucleotides, and translate it into proteins, or amino acids. tRNA transport amino acids to ribosomes for the assembly of protein.

Option C is correct.

c. in the nucleus of the cell

Transcription is the process of making mRNA from the strand of DNA. In this way the message of DNA is encoded into RNA. Transcription always occurs in nucleus of the cell.