A jockey feeds a carrot to his horse first thing in every morning. The horse now "neighs" every morning when it sees the jockey. Neighing is a(n) _*learned*_ response to the carrot provided by the jockey, an _*external*_ stimulus.
Also, just as a heads up. I saw the previous person posted a link. Remember not to click any links that lead to domains which are unknown to you. They could hold a virus.
