In a series circuit, the electrons flow through the wire and each of the bulbs before they return to the battery. true or false

True.

Explanation:

The current comprise of electrons which moves in the circuit in only one direction. In a series circuit, there is only a single path for the flow of current and so the electrons flow through the wire and each of the bulbs which are present in this path before they return to the battery which connected on the other end of the circuit. The current which is received after the flow of current through the circuit has low number of electron due to usage by the bulb and resistance of wire.

its temperature is increasing. this causes molecular vibrations to increase.

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

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.