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.
Definition: An Astronomical Unit is the mean distance between the Earth and the Sun. In 2012, the International Astronomical Union defined the distance to be 149,597,870,700 meters. Historical Background: Tycho Brahe estimated the distance between the Sun and the Earth at 8 million kilometers (5 million miles).Later, Johannes Kepler estimated the AU was at 24 million kilometers (15 million miles).In 1672, Giovanni Cassini made a much better estimate by using Mars.istorical Background: Tycho Brahe estimated the distance between the Sun and the Earth at 8 million kilometers (5 million miles). Later, Johannes Kepler estimated the AU was at 24 million kilometers (15 million miles).