What is the basic unit of heredity in living organisms?

The basic unit of heredity in living organisms is the gene. A gene is a segment of DNA that contains the instructions for building proteins, which are crucial for the structure, function, and regulation of the body's cells, tissues, and organs. Genes determine inherited traits and are transmitted from parents to offspring during reproduction. They function as the fundamental units that carry information necessary for the development and functioning of all living organisms.

While chromosomes, which are structures made up of DNA and proteins, play a crucial role in heredity by holding many genes, they are not the basic unit of heredity themselves but rather a collection of multiple genes organized together. RNA and proteins are also essential biomolecules, but RNA primarily serves as a messenger that conveys genetic information from DNA to the cellular machinery that produces proteins, while proteins are the functional products of gene expression rather than units of heredity. Thus, the definitive unit that encapsulates the concept of heredity is the gene.