Joseph is taking amphetamines to combat fatigue during his workout. this may not be a good idea because a. amphetamines may cause liver and kidney damage if used for an extended period of time b. amphetamines may cause depression and fatigue after the effect wears off. c. amphetamines tend to increase blood viscosity and can cause fatal blood clots d. amphetamines tend to have a negative impact on the metabolic rate and will cause weight gain