Species X and species Z belong to the domain.
Answer: Option A.
Step-by-step explanation:
Species which belong to the same domain, they also belong to the same kingdom and also to the same phylum. These species are very similar to each other and can also produce offspring together.
In the information given, species X and species Y belong to the same domain. The next column says that the species Y and species Z also belong to the same domain. So species X and species Z will also belong to the same domain.