Answer:
A marker that is genetically inherited
Step-by-step explanation:
A biological marker, in the strictest sense, is a characteristic of a living being that allows us to identify it.
Examples of biomarkers are: physical (colour, size, shape, etc.) and biochemical (composition, metabolic pathways, secretions). Currently, advances in technology have allowed us to use highly precise tools, such as molecular markers: genomics (SNPs, TSR, microarrays, and others) and proteomics.
Regardless of the nature of the marker, the important thing is that it can be inherited, as this guarantees that one can identify, for example a species, by the presence of a gene, independently of the individual sampled.