Answer:

Explanation:
Hello,
In this case, since in a dilution process the moles of the solute must remain unchanged, we use the volumes and molarities as shown below:

Clearly, the concentrated solution is 12M and the diluted solution is 0.5 M, thus, the volume of the concentrated solution we should take is:

Best regards.
North Pole ,land is the answer
For the answer to the question above, one of the most important risks to take into account regarding the mining of uranium is the possibility of nuclear decay taking place and contaminating the worker. So I believe the answer is the last one which is <span>the health hazards that are associated with uranium mining</span>