PCR is a technique that:

1. Provides a statistical analysis of the nitrogenous-base pairings.

2. Can produce many exact copies of segments of DNA.

3. Produces information regarding the sequence of nitrogenous bases.

4. Virtually eliminates operator error from DNA analysis.

The correct answer is 2. Can produce many exact copies of segments of DNA.

Explanation:

Polymerase chain reaction is a method that is invented by Karry Mullis and is widely used to make several copies of a DNA segment. PCR has three main steps by which a DNA segment gets replicated.

1. Denaturation: During the denaturation step, a DNA segment is converted into single-stranded by raising the temperature to 95° Celcius for 30s.

2. Annealing: During annealing temperature is reduced so that primer can bind on the separated DNA strands.

3. Extension: In extension, DNA polymerase adds nucleotide and extends the new strand of DNA. The temperature in this step is 72°c.

This cycle is repeated many times to get appropriate numbers of DNA copies.