Isotopic evidence refers to the analysis of the stable isotopes of elements present in various materials, such as rocks, minerals, water, and biological tissues. By studying the ratios of different isotopes, researchers can gain insights into a wide range of processes, including the origins of materials, environmental conditions, and biological interactions. Isotopic evidence is commonly used in fields such as geology, archaeology, ecology, and forensic science to track the movement of elements through different systems, identify sources of contamination, and reconstruct past environments. This type of evidence can provide valuable information for understanding Earth's history, human evolution, and modern environmental issues.