Answer: D. The genes contained in an organisms genetic makeup.
Explanation: Genotype is the genetic makeup of an organism. Every trait in living organisms is controlled by a pair of gene, the genes for the trait is called genotype. These genes can be dominant or recessive. Traits such as height, skin colour, tongue rolling, eye colour, blood type are controlled by at least a pair of gene. Genes that control height such as TT, Tt and tt are the genotypes for height. Gene for brown eye B and gene for blue eye b can occur in pair either in a homozygous or heterozygous state as BB, Bb and bb. These pairs of genes are the genotypes.