Read the passage. John eventually went to college at the University of Montana, where he took care of some captive bears for the same scientists. After college, he joined the Peace Corps and went to Cameroon in Africa. There he got interested in the conservation of African wildlife and hoped to make that his specialty. But a motorcycle accident cost him his spleen, making it dangerous for him to work in the tropics. Which is the best inference that can be made about this passage?