Concept:Inbreeding refers to the mating of animals that share a close genetic relationship through common ancestry.
Explanation:Animals that are closely related, such as parent and offspring or siblings, share many of the same genes.
When such animals are mated, the practice is called inbreeding.
Inbreeding increases homozygosity, meaning offspring inherit identical alleles from both parents.
It is often used to preserve desirable traits within a breed, but it can also increase the risk of inherited defects.
This is different from outbreeding, which involves mating unrelated animals, and crossbreeding, which combines different breeds.
Pen mating is not the standard term for mating closely related animals.
Therefore, the correct option is inbreeding.
Answer:D. inbreeding