Question

An organism's ________ is the way its genotype is expressed

Answer 1

The answer is Phenotype.

Phenotype is the observable traits on the organism which are mainly influenced by how the genotype of the organism interacts with the environment. An example of how phenotype is determined is when a gene has several alleles. The dominant alleles are expressed in phenotype while the recessive one is masked. Epistasis of alleles also occurs in many other cases.  

Answer 2

To complete your sentences the correct answer  is  Genotype & Phenotype