The answer is A .
PCR stands for Polymerase Chain Reaction. It is a method to analyze a short sequence of DNA or RNA and is used to reproduce (amplify) selected sections of the nucleic acid. Untold numbers of copies can be made of the DNA in just a few hours.
PCR amplifies the regions of DNA that it targets and can therefore be used to analyze extremely small amounts of sample. This is often critical for forensic analysis, when only a trace amount of DNA is available as evidence.
The ice has less density than liquid water, so it floats on the water surface. Therefore during the winter all the lakes and rivers are frozen only at a top. Deeper layers of water are cold, but still liquid and it allows fish and other organisms to survive. Moreover, the ice cover provides temperature isolation so liquid water beneath the ice has more or less constant temperature (around 4 dgr Celsius)
Families I think, pretty sure
A - Ff and Ff is the answer
