Read the excerpt from How Hurricanes Form. Hurricanes are the largest and most violent storms on Earth. They are large rotating storms with high speeds that form over warm waters. These storms are known as hurricanes in North America and the Caribbean. However, they have different names in other regions. In South East Asia, they are called typhoons. In the Indian Ocean, they are known as cyclones. Hurricane winds move at the speed of at least 74 miles per hour. They can be as wide as 300 miles. But, how are these huge storms formed?

a world map showing that hurricanes occur north of the equator in the Atlantic Ocean, cyclones occur north and south of the equator in the Indian Ocean, and typhoons occur north of the equator in South East asia

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.

Select the statement that explains how hurricanes start to rotate. (2 points)

a
Cool, moist air swirls inwards to fill the high pressure area in the center.

b
Cool, moist air swirls inwards to fill the low pressure area in the center.

c
Warm, dry air swirls inwards to fill the high pressure area in the center.

d
Warm, moist air swirls inwards to fill the low pressure area in the center.