Which neurotransmitter is responsible for the voluntary movement of muscles in your arm? see section 43.3 ( page 909) ?

The neurotransmitter that is responsible for the voluntary movement of muscles in the arm is ACETYLCHOLINE.
Acetylcholine is the neurotransmitter that act at neuromuscular junctions, that is, it is released by the nervous system to activate muscle movement. Muscular contraction is usually initiated by the release of acetylcholine by the nervous system.

Answer:

it provides an alternative energy pathway for the reaction to proceed.

explanation:

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.

We are not able to see the stars. light prevents our seeing the stars. i hope it kinda : )