News. The invention of the Polymerase Chain Reaction (PCR) radically changed biology. The technique was considered so important that the Nobel Prize was awarded to its inventor, Kary Mullis, in 1993.Thanks to this technique, very small samples of DNA (from as little as a single cell) can be analyzed.ews. The invention of the Polymerase Chain Reaction (PCR) radically changed biology. The technique was considered so important that the Nobel Prize was awarded to its inventor, Kary Mullis, in 1993.
The smallest prime number, according to primality as defined by modern mathematicians, is 2. To be prime, a number must be divisible only by itself and 1. All other numbers are known as composites.
Demonstration, with Cuisenaire rods, that the number 7 is prime, being divisible only by 1 and 7. A prime number (or a prime) is a natural number greater than 1 that has no positive divisors other than 1 and itself. A natural number greater than 1 that is not a prime number is called a composite number. For example, 5 is prime because 1 and 5 are its only positive integer factors, whereas 6 is composite because it has the divisors 2 and 3 in addition to 1 and 6.