Final answer:
The traits that are part of a linkage group on chromosome 19 are those that are located near each other on this chromosome and are inherited together, such as brown hair and brown eyes due to reduced crossing-over.
Step-by-step explanation:
The question pertains to genetic linkage, which is a fundamental concept in Biology that explains why certain traits tend to be inherited together. The traits that are part of a linkage group on chromosome 19 would be those physically located near each other on this chromosome. For instance, genes for brown hair and brown eyes are examples of linked traits because they are often inherited together due to their proximity on the same chromosome, which reduces the likelihood of these genes being separated during crossing-over events that occur during meiosis. However, without specific gene information related to chromosome 19, it is not possible to determine which traits in a given list would be linked on that chromosome.