Species X is an extinct animal. A scientist has discovered fossils of species X and compared them to species Y, a living animal that inhabits the same area where the fossils were found. The scientist has noted that the two animals share several physical characteristics.

What can the scientist most likely conclude about the two types of animals?

Species X was better adapted to the environment.
Species X outcompeted species Y for food.
Species X is an early ancestor of species Y.
Species X mated with species Y and had unique offspring.
The siblings are more closely related to each other than they are to their grandparents.
Each sibling is more closely related to the grandparents than to the other sibling.
The grandparents do not have any shared characteristics in common with the siblings.
The grandparents do not have any shared characteristics with one another.