The observable expression of genes present in an organism is called phenotype.

Here's a breakdown:

* Genotype: The genetic makeup of an organism, represented by the specific genes it carries.

* Phenotype: The observable characteristics of an organism, resulting from the interaction of its genotype with the environment.

For example, a person might have the gene for blue eyes (genotype), and as a result, have blue eyes (phenotype). However, the environment can also play a role in how genes are expressed. For example, a person with a gene for height might not reach their full potential height if they experience malnutrition.