Which item is necessary for proper visibility during adverse weather conditions?

The heater and defroster are essential for maintaining proper visibility during adverse weather conditions, such as rain, snow, or fog. They work by warming the air inside the vehicle and directing it toward the windshield, which helps prevent the formation of ice or condensation that can obscure your view. When visibility is compromised by moisture, the defroster keeps the glass clear, allowing the driver to see the road and surrounding environment more effectively.

While additional lighting, windshield tinting, and extra mirrors may contribute to overall visibility and safety, they do not directly address the issue of dealing with moisture buildup on the windshield or maintaining a clear line of sight during conditions like freezing temperatures or heavy rain. The heater and defroster specifically target the problem of obstructed views caused by weather, making them crucial for safe driving in such conditions.