C. R. stands for "Cumulative Risk," which refers to the total risk that an individual or community faces from various sources over time. This concept is often used in fields like public health and environmental science to assess how multiple factors, such as pollution, socioeconomic status, and lifestyle choices, can combine to affect overall well-being. C. R. is important for understanding how different risks interact and contribute to health outcomes. By evaluating cumulative risk, researchers and policymakers can develop more effective strategies to mitigate risks and improve health, particularly in vulnerable populations who may face higher cumulative exposures.