Before using any chemical in the lab, why should one first read the material safety data sheet (msds)?

this is important for laboratory safety.
the msds tells where to purchase chemicals.
the msds provides the chemical formulas.
this is important for analyzing experiments.

answer: i don't know

explanation:

you need to provide a picture, otherwise i can't tell you.

if you can provide one, i'd be more than happy to you with this!

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.

answer:

convection currents in the magma drive plate tectonics. heat generated from the radioactive decay of elements deep in the interior of the earth creates magma (molten rock) in the aesthenosphere. the aesthenosphere (70 ~ 250 km) is part of the mantle, the middle sphere of the earth that extends to 2900 km.