20. A research company wants to design a new type of artificial heart valve that will be less likely to be rejected by a person's immune system. Which step in the design process should the company perform before building a prototype of the heart valve? A. Find test subjects for the new heart valve.
B. Conduct research on existing artificial heart valves.
C. Determine how to manufacture the new heart valve.
D. Evaluate the performance of the artificial heart valve.

C. Determine how to manufacture the new heart valve.

I think it seems a little obvious (I'm probably wrong)because obviously before doing something important your going to think about how to do it first.

Answer :B

Explanation: Conduct research on existing artificial hart valves

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.