premise: the fossils of horse has shorter bones in lower levels and the fossils of horse has longer bones in the upper level sent2: an animal is a kind of organism sent3: younger layer of rocks are on top of the older layer of rocks according to superposition sent4: a horse is a kind of animal sent5: if fossils of an organism change depending on the level in which they were found then that species of organism changed over time.
hypothesis: horse species have changed from smaller to larger over time