What are individual units of inheritance known as?

The individual units of inheritance are known as genes. Genes are segments of DNA that contain the instructions for producing proteins, which ultimately determine the traits and characteristics of an organism. Each gene can vary in form, leading to different traits, such as color, size, or behavior in horses.

While chromosomes are the structures that house many genes, they are not the individual units themselves. Chromosomes are composed of tightly coiled DNA and serve as carriers of genetic information.

Alleles refer to the different versions or variants of a gene that can exist at a particular location on a chromosome. While they are related to inheritance, they are not standalone units of inheritance, but rather variations of a specific gene.

Codons represent sequences of three nucleotides in DNA or RNA that correspond to specific amino acids in protein synthesis. They are important for the translation of genetic information but do not represent units of heredity.

Thus, genes are the fundamental hereditary units that convey genetic information from parents to offspring, making them the correct answer to the question.