What is one potential long-term effect of high radiation exposure?

High radiation exposure is well-documented to lead to an increased risk of cancer as one of its significant long-term effects. This occurs because radiation can damage the DNA within cells. If the damage is not properly repaired, it can lead to mutations that may result in uncontrolled cell growth, which characterizes cancer development. Different types of radiation can affect various tissues and organs, contributing to the likelihood of developing different cancers depending on the level and duration of exposure.

The other choices provided do not align with the established understanding of radiation's effects on health. Improved immune system function and enhanced cognitive abilities are not associated with high radiation exposure; rather, high levels of radiation can compromise the immune system. Normal physical development can also be adversely affected due to radiation, especially in young or developing organisms, rather than being a positive outcome. Thus, the link between high radiation exposure and increased cancer risk is well-supported by research and stands as a critical point of concern for radiological workers.