define the following terms

DNA , GENE . GENETIC DRIFT , SPECIATION , GEOGRAPHICAL ISOLATION

DNA (Deoxyribonucleic acid) is a genetic material that containing the genetic instructions used in the development and functioning of all known living organisms. It helps to transmit genetic information from parent to offspring. It carries all the instructions for making proteins in the cell.

Gene is a unit of inheritance made up of the segments of DNA (chromosome). It controls a particular character in an organism.

Genetic drift - The process of change in the genetic composition of a population due to random events rather than by natural selection, resulting in changes in allele frequencies over time. Drift is observed most strongly in small populations and results in changes that need not be adaptive.

Speciation may be defined as an evolutionary process, which involves the formation of one or more species from an existing species.

Geographical isolation is isolation of a species or a group of individuals from others by means of some physical (geographical) barrier like river, mountain,big glacier etc. As the result of geographic isolation, the two species are reproductively isolated. Geographical isolation results in evolution of new species.