<span>the interference of two waves of equal frequency and opposite phase, resulting in their cancellation where the negative displacement of one always coincides with the positive displacement of the other.</span>
It's known as severity.
The fact that her pain is on the scale between 1-10 refers to the severity of her pain.
Hope that helped ^U^
It becomes positive because ATP synthase allows H+ ions to pass through the membrane .
The law of conservation of mass states that the mass will stay constant given a chemical reaction because no atoms were created or destroyed. This being said, an example can include water evaporating in a clear bottle outside on a hot day ( the mass of the bottle will stay the same, but the liquid water evaporated into gaseous water).
