Why is the question of whether the injuries came from a stone or steel weapon important? how could scientists distinguish between the different types of weapons?

It is important in determining whether injuries/death was an accident or purposeful, and if purposeful, who, how and why did someone do it. They determine the weapon through the ligature marks left, the shape, force and impact of the injury, the location of the injury, and by analysing any fragments and trace evidence left on the wound

what statement best describes the difference between the sympathetic and parasympathetic nervous systems?

the sympathetic nervous system prepares the body for intense physical activity and is often referred to as the fight-or-flight response. the parasympathetic nervous system has almost the exact opposite effect and relaxes the body and inhibits or slows many high energy functions.