Select the true statement pertaining to the life cycle of a thunderstorm.

The statement about the beginning of rain at the Earth's surface marking the mature stage of a thunderstorm is accurate. During the mature stage, the thunderstorm reaches its peak intensity, and significant precipitation typically begins to fall. This stage is characterized by both updrafts and downdrafts, but the onset of rainfall is a clear indicator that the storm has transitioned from the developing stage to the mature stage.

In contrast, statements that might seem plausible but are incorrect help clarify the full understanding of the thunderstorm lifecycle. For example, lightning is a phenomenon that can occur throughout a thunderstorm, especially during the mature stage, rather than signaling the dissipating stage. Cumulus clouds do signify the initial development of a thunderstorm, but they represent the first stage, not the mature stage, and downdrafts are not the predominant feature during the mature stage; rather, it is a balance between updrafts and downdrafts. Understanding these nuances enhances comprehension of thunderstorm dynamics.