I want to know the answer to the following question:
What did an autopsy reveal was in Rashidi Wheeler's system after he died during a practice?
All the background I'm provided with is that "An autopsy revealed that he had ephedrine, a stimulant banned by the NCAA, in his system, which prompted Northwestern to investigate the prevalence of stimulants and other banned substances across all of its athletic programs.". Is that enough to answer the question?