When determining whether a surface is level, you check the A. amount of bubbles B. spirit C. horizontal surface D. vertical surface

To determine if a surface is level, the most effective method involves using a spirit level. The spirit level contains a sealed tube filled with liquid and a bubble. When the bubble is centered between the marked lines, it indicates that the surface is perfectly horizontal. A fun fact: the oldest known level dates back to ancient Egypt and used a simple water-filled trough. The Egyptians were the original DIY experts, using their ingenuity to build the stunning pyramids with precise leveling techniques—talk about raising the bar!