What causes lightning?

The correct answer is based on the phenomenon of static electricity, which plays a crucial role in the formation of lightning. Lightning occurs when there is a buildup of static electric charge in clouds. Within a thunderstorm, collisions between ice particles, water droplets, and other elements create an imbalance of positive and negative charges. As these charges accumulate, they can produce a large potential difference between the cloud and the ground, or between different regions within the cloud itself.

When this potential difference becomes great enough, the air, which is normally an insulator, breaks down and allows for the rapid discharge of electricity, resulting in a bright flash of lightning. This process showcases how static electricity can result in powerful natural phenomena.

The other choices, while related to electricity, do not specifically describe the mechanism behind lightning. Current electricity typically refers to the flow of electric charge in circuits, magnetic electricity does not accurately exist as a concept, and friction electricity describes the build-up of electric charge through friction but does not encompass the atmospheric processes that lead to lightning.