Polymerase chain reaction (PCR) is a laboratory technique used to amplify DNA sequences. The method involves using short DNA sequences called primers to select the portion of the genome to be amplified.olymerase chain reaction (PCR) is a laboratory technique used to amplify DNA sequences. The method involves using short DNA sequences called primers to select the portion of the genome to be amplified.
The smallest possible size for anything in the universe is the Planck Length, which is 1.6 x10-35 m across.
The nearest star is about 24 trillion miles away. That is 24,000,000,000,000 miles. If a scientist wanted to do a math problem with that huge number it would be very difficult. To make this number smaller we use something called light years.