Water boils at a lower temperature on the hills because A. It is cold on the hills B. There is less carbon dioxide on the hills C. There is a decrease in air pressure on the hills D. There is less oxygen

The correct answer is C. There is a decrease in air pressure on the hills.

Air pressure is the force exerted by the weight of the air above a given point. The higher you go, the less

At sea level, water boils at 212 degrees Fahrenheit (100 degrees Celsius). However, at an elevation of 10,000 feet (3,048 meters), water boils at 194 degrees Fahrenheit (90 degrees Celsius). This is because the air pressure at 10,000 feet is about half of what it is at sea level.

The lower air pressure at higher elevations means that the water molecules have less weight pressing down on them. This allows them to escape from the liquid state

Options A and B are incorrect because there is no evidence to suggest that the temperature or carbon dioxide levels are different on the hills. Option D is incorrect because oxygen is not a factor in the boiling point of water.