Why is heating a first step in pcr amplification of extracted dna?
the enzyme dna polymerase works at a higher temperature.
it permits hydrogen bonds between dna strands to dissociate.
the nucleotides bind together at high heat.
it is required for primers to bind permanently to the dna.
it is necessary for dna strands to anneal to each other.

Option). It permits hydrogen bonds between DNA strands to dissociate.

Explanation:

PCR (polymerase chain reaction) techniques can bed defined as a technique, which is used for in vitro amplification of sample DNA. It is made up of three steps, denaturation, primer annealing, and extension.

The first step in PCR is heating of sample DNA to denature the double stranded DNA by breaking hydrogen bonding present between bases of double stranded DNA.

Due to this, double strands of DNA get separated and provide templates for synthesis of daughter DNA strands.

Thus, the correct answer is second option.

format change of dna.  

this would be called india