Which is a method of making many copies of DNA? O A. Nuclear transfer
B. Gel electrophoresis
C. Reverse transcriptase
D. Polymerase chain reaction

D. Polymerase chain reaction

Explanation:

PCR is very percise; used to amplify or copy a specific DNA target from a mixture of DNA molecules by:

two short DNA sequences (primers) are bind to start and end the DNA targetperform the PCR; DNA templates is added to a tube that contains primers, free nucleotides, and the enzyme (DNA polymearse)it is mixed in a PCR machine that increases and decreases the temperature of the samplemixture is heated to seperate the double strnaded DNA templated into single strandsmixture is cooled so the primers can bind to the DNA templatethe DNA polymerase will synthesize to new strands of DNA from the primersduring synthesis, the end of the first cycle, the DNA molecule will consist of a new and old DNA strandPCR continues with added cycles to repeat the stepsnewly synthesized DNA segements serve as templates in later cycles; which can be copied over and over.