The correct answer is lower central air pressure. When the central air pressure drops in a hurricane, it creates a pressure difference between the center of the storm and the surrounding atmosphere. This pressure difference causes the surrounding air to rush in towards the center, resulting in high wind speeds. Thus, a lower central air pressure in a hurricane causes it to increase in strength and intensity. However, it is important to note that cooler water temperatures can eventually weaken a hurricane as it moves over cooler ocean areas. Moving onto land can also cause a hurricane to lose strength because it disrupts the storm's access to warm and moist air.
