The horse one is debatable. From the wiki page Evolution of the horse for example - "Paleozoologists have been able to piece together a more complete outline of the evolutionary lineage of the modern horse than of any other animal. Much of this evolution took place in North America, where horses originated but became extinct about 10,000 years ago."
Seems that they originated and spread from the New World, went extinct there, and were then reintroduced again from the Old World when the Spanish arrived.
That said, the wording of the instructions could stand to be clearer. Or, it may make sense to simply change "horse" to some other plant or animal for which there's no potential ambiguity.