I believe the term for an observable trait of an organism would be called or noted as the organism's phenotype.
Variation means difference in genetic makeup between individuals within a specie.
There are three stages in the life cycle of a spider : - the first is embryonic stage, then the larval stage and finally nympho- imginal stage.
Developing a coelom made nutrients more easily absorbed by roundworms. A coelom is a fluid filled cavity developed in the mesoderm and it is the main body of a roundworm. It contains the digestive tract and many other organs.
The mechanism is straightforward: in Metaphase one of Meiosis, chromosomes line up in two lines, with homologous across from each other, which allows them to interact by crossing over. In Metaphase of Mitosis, the chromosomes are all lined up single file, so the homologous chromosomes cannot interact.
