<em>The genotype of an organism determines its phenotype</em>. Phenotype is constituted by observable characteristics of an organism. These characteristics are codified by genes, and the combination of the differents variants of a gene which codify a phenotipic characteristic constitutes the genotype. For example: eyes color is a characteristic. Its is codified by variants of a gene. The combination of two variants of a gene gives a genotype, which codifies for the phenotype 'blue eyes'.
