Answer:
RADON GAS
Explanation:
This is the main source of indoor radon. It flows through the air, ground and surface water. It primarily finds it's way through the soil into buildings and into water supplies. Once it escapes from soil, it discharges from emission stacks into the air.
I think it’d be both because it can be physical ex: bodybuilding
And can be mental as well since we can strengthen our brain
hope this helped
