What is the study of genes, their inheritance, and their expression known as?

The study of genes, their inheritance, and their expression is best defined as genetics. This field focuses on understanding how traits and characteristics are passed from one generation to the next, including the mechanisms of heredity and variation in living organisms. It encompasses a wide range of topics, including the structure and function of genes, the patterns of inheritance, genetic mapping, and the role of genes in development and disease.

Genomics, on the other hand, refers to the comprehensive analysis of genomes, which includes not just the study of individual genes, but also the interactions between genes and how they work together as a complete set of genetic material in an organism. Bioinformatics involves the use of computational tools to analyze and manage biological data, particularly in the context of genomics. Epigenetics covers the study of changes in gene expression that do not involve alterations to the underlying DNA sequence, focusing on how environmental factors and lifestyle can affect gene activity.

In summary, genetics specifically addresses the core concepts of heredity, gene function, and expression, making it the correct answer in this context.