Question

Why is PCR an extremely valuable tool for the molecular biologist?

Answer 1

Molecular biologists usually work on DNA.

Explanation:

Usually the isolation and working on the DNA is a tedious process because, DNA is too small to be visible with the naked eyes. And on performing the isolation of DNA a very little amount can to isolated .
And it is impossible to repeat the process of isolation of DNA to attain the amount of DNA that can be worked upon. And hence pcr is used to amplify the amount of DNA by making number of copies of it, through which desirable amount of DNA can be obtained and can be worked upon.
So, pcr is one of the basic steps used by molecular biologists.