A) Salt, because salt can easily dissolve in water. Oil would not dissolve or evaporate in water (think of an oil spill - does that oil dissappear?). Aluminum foil would definitely not dissolve in water, so it is not soluble.
Answer:
I don't know if this is right but try it. The amount of water vapor in the air is called absolute humidity. The amount of water vapor in the air as compared with the amount of water that the air could hold is called relative humidity. This amount of space in air that can hold water changes depending on the temperature and pressure.
Answer:
Widening of blood vessels.
Explanation:
The reduction of aldehydes, ketones, organic acids causes the formation of alcohols that is used for different process in the human body. This alcohol increase the width of the blood vessels as it enters the bloodstream causing greater flow of blood to the skin surface as well as temporary feeling of warmth. It also increased heat loss and rapid body temperature decrease that produces cooling effect in the body.