Whether the District Court committed plain error by allowing the government to convert a sentencing factor into a proximate cause element

QUESTION PRESENTED Whether the District Court committed plain error by allowing the government to convert a sentencing factor, “resulting in death,” under 21 USC §841(b)(1)(c) into a proximate cause element and then prove that sentencing factor to a jury through evidence about the evils of heroin that was irrelevant and unfairly prejudicial.