Rock layers, also known as strata, are distinct layers of rock that form over time through various geological processes. These layers can vary in thickness, composition, and color, often reflecting changes in the environment where they were deposited. For example, sedimentary rock layers are typically formed from particles that settle in water, while volcanic layers can result from lava flows. The study of rock layers is important in understanding Earth's history and the processes that shape it. Geologists use the principle of stratigraphy to analyze these layers, helping to identify the age of rocks and the events that led to their formation. This information can reveal insights about past climates, ecosystems, and even the presence of fossils.