Read the excerpt from How Hurricanes Form. Hurricanes are often compared to engines. Just like engines, they need a type of fuel. Hurricanes form over warm ocean waters near the equator. For hurricanes, their fuel is warm, moist air. When hurricanes form, the warm, moist air above the ocean rises upward from close to the surface of the water. Because the warm air rises, it results in less air under the surface of the water. This area with less air is known as an area with low pressure.

Air from areas surrounding this low pressure space pushes in to the area. This fills the low pressure area. The new air in this space becomes warm and moist and also rises. As the air continues to rise, the air surrounding the space swirls in to take its place. This process of air swirling in to replace air that has risen continues. Eventually, the moisture in the air forms clouds.

The wind and the clouds that form create a system. A system is a pattern of weather. The system of clouds and winds continues to spin and grow. The water evaporating from the ocean's warm surface acts as the fuel, which is what helps this spinning and growing. The system rotates faster and faster until the eye of the storm forms in the center area. Ironically, the eye of the storm is the calmest part, and it has very low air pressure. The higher pressure above the hurricane continually flows down into the eye.

Select the detail from the excerpt that supports the main idea of this part of the article. (2 points)

a
Hurricanes are often compared to engines.

b
The eye of the storm is the calmest part of the storm and has very low air pressure.

c
The water evaporating from the ocean's warm surface acts as the fuel.

d
This process of air swirling in to replace air that has risen continues.