Final answer:
Without a specific phylogenetic tree provided, we cannot determine which species is most closely related to Bos taurus. In general, the closest relative is found by identifying the species sharing the most recent common ancestor on the phylogenetic tree.
Step-by-step explanation:
To determine which species is most closely related to Bos taurus (cattle), we need to look at a phylogenetic tree. The species that shares the most recent common ancestor with Bos taurus is the species that is most closely related. While the student's question mentions different scenarios with phylogenetic trees and relationships amongst species, without an actual diagram provided, we cannot specifically identify the closest relative to Bos taurus.
If we had a phylogenetic tree showing Bos taurus with other species, we would look for the branch that diverges most recently with it. To answer the question accurately, it is essential to review the specific phylogenetic tree presented in the question.
The species most closely related to Bos taurus in the given phylogenetic tree is Bos indicus. The two species are both members of the Bos genus and share a more recent common ancestor compared to other species on the tree.