Hydrogen is composed of H atom and oxygen is composed of O atom. For water, it is composed by both H and O atom. If you burn hydrogen in oxygen, you can get water. And if you electrolysis water, you can get hydrogen and oxygen.
Answer: Boyle's Law
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Boyle's Law is the pressure-volume law and it relates pressure and volume at constant temperature. Boyle's law states that pressure and volume vary inversely, meaning that as one goes up, the other one goes down.
The correct answer is b, 18 protons