Answer:
There are 193 member states. The UN recognises 206 states altogether.
Explanation:
The potentially harmful effects of mining can be reduced by A. Flushing mines with water.
Both are used to produce energy to be used as electricity
We can use the equation

to calculate the frequency.
Rearranging this gives us

.
So the frequency is

, which equals 0.42 hertz
(to 2 decimal places).