Residents of which of the following cities would probably receive the most exposure from naturally occurring radioactive minerals?

Residents of Vale, California, would probably receive the most exposure from naturally occurring radioactive minerals due to the geological characteristics of the region. Vale is situated in an area with a history of mining and known deposits of uranium and other radioactive minerals. Natural sources of radiation can include uranium, thorium, and radon, which may accumulate in certain rock formations and soil.

In addition to mining operations that may expose residents to higher levels of radiation, the geological structures in this area are more likely to contain uranium-rich minerals. The presence of such minerals, when disturbed or exposed, can lead to increased radiation levels in the environment, which residents may then be exposed to.

In contrast, other cities listed do not have similar geological conditions or histories of significant mining operations. For instance, Portland, Fort Myers, and Chicago have geological compositions and urban settings that contribute to lower prevalence and risk of exposure to naturally occurring radioactive materials. Therefore, Vale, California, stands out as the location with the highest potential exposure to naturally occurring radioactive minerals.