How is a genome defined in biological terms?

A genome is defined as the complete set of genetic material within an organism. This includes all of the organism's DNA, which encompasses not only the genes (the segments of DNA that encode proteins) but also non-coding regions that play roles in regulation and other functions. The genome contains the hereditary information that can be passed from one generation to the next, providing instructions essential for growth, development, and functioning.

Understanding the genome is fundamental to various fields of biology and medicine because it influences traits, behaviors, and susceptibilities to diseases. By studying genomes, researchers can gain insights into evolutionary biology, genetic diversity, and the basis of various genetic disorders.

The other choices, while related to biological concepts, do not define a genome. The proteins in an organism are products of the genes encoded in the genome, but they do not encompass the entire genetic material. The total number of cells relates to the organism's cellular structure rather than its genetic information. Variances in an organism's traits refer to phenotypic expressions influenced by genetic and environmental factors, but they do not capture the complete genetic framework that is the definition of a genome.