Final answer:
Two loci are considered physically linked because they are close together on a chromosome, leading their alleles to be inherited together. A multilocus genotype is the combination of alleles at more than one locus in an individual.
Step-by-step explanation:
Two loci that are close together on the same chromosome are considered physically linked because their alleles are more likely to be inherited together during meiosis. This is known as the linkage phenomenon. When alleles are close together, they tend to travel as a package during the formation of gametes, which means they are transmitted to offspring in combinations that reflect those in the parental organisms.
A multilocus genotype is referred to as a combination of alleles at multiple loci that are transmitted to an individual. It provides a comprehensive genetic description for an individual at more than one locus, and this information can be used to trace inheritance patterns, assess genetic diversity, and study the genetic structure of populations.