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.
where. 1  D {\displaystyle D} is the distance of closest distinct vision (usually 250 mm) 2  D E O {\displaystyle D_{\mathrm {EO} }} is the distance between the back focal plane of the objective and the back focal plane of the eyepiece (called tube length), typically 160 mm for a modern instrument.