Why is using reverse transcriptase necessary for finding a way to make artificial insulin

Melting glaciers is a serious threat to the environment what is the possible consequence of melting glaciers on polar bears?

Most of the carbon on earth is stored in the form of

What does polymerase chain reaction (pcr) do? o a. separates dna fragments by size o b. cuts a dna sample into fragments o c. provides an overall picture of a person's chromosomes o d. makes more copies of a sample of dna