2. Why is atmospheric pressure greater at lower elevations than higher elevations? A. Sunlight warms the air. B. Gravity pulls the air downward. C. Oceans are located beneath the air. D. There is a difference in humidity.

## Step 1<br />Atmospheric pressure is the force exerted by the weight of the air above a given point. It is important to understand Earth's atmosphere is held close to the Earth's surface by gravity. <br /><br />## Step 2<br />As we move higher from the Earth's surface, the amount of air above us decreases. This means there is less air to exert pressure. <br /><br />## Step 3<br />Therefore, the atmospheric pressure decreases as we move higher from the Earth's surface. This is because gravity pulls the air downward, creating a greater pressure at lower elevations than at higher.