Human beings have wondered how it was that cats produce kittens, dogs produce puppies, human beings produce human babies, and the young are faithful reproductions of the parents. Scientists have discovered that every cell contains a set of instructions about how to reproduce itself, function, repair itself, and grow. Every cell in an organism's body contains the same set of chromosomes. People have family resemblances because they share some of the same chromosomes, and therefore have characteristics in common. The earliest form of reproduction is asexual reproduction .
Single cells make copies of their chromosomes and divide into two cells.
They thrive in identical conditions, and are stressed by the same environmental changes. Chromosomes are made up of millions of short sequences of amino acids called genes. The genes influence, and sometimes determine absolutely, the characteristics that the organism will express. When sexual reproduction occurs, the new organism gets chromosomes from each of its parents. This makes each new organism unique.