Answer:
There are often not more than one or two independent variables tested in an experiment.
A. A pacemaker
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If ice is warmed and becomes a liquid, the process is endothermic.
The process requires heat in order to proceed. If ice stays in a very cold place, it will not melt unless it's heated. If ice is placed outside where it melts on its own, it gets the heat from the surroundings.
Answer:
gain or loses electrons.
Explanation:
Because the atom need to be balanced.
