Answer:
Clay
Explanation:
Radon -
Radon is one of the radioactive noble gas , It is highly radioactive , hence , is dangerous for health . Radon is formed by the radioactive decay of the uranium into Lead .
The half life is equal to 3.8 days .
Radon is is very dense in nature .
Since , radon is a noble gas so , it does not react with the surroundings .
In the clay , the radon gets lost immediately from the source rock through the fractures .
