<em>The correct option is B) Their offspring cannot breed.</em>
Explanation:
Organisms belonging to the same species require the ability to breed and produce fertile offsprings. If two organisms breed to produce infertile offsprings, then they are not considered to belong in the same species. Infertile offsprings do not have the capability to reproduce. The breeding between a horse and a zebra produces zorse, which is sterile. This depicts that both the zebra and horse belong to different species as they cannot produce a fertile offspring.
He inferred that similar changes had happened in the past. Uniformitarianism combines the idea of gradual change over time with Lyell's observations that such changes have occurred at a constant rate and are ongoing.
