A new energy source found in the ocean that is currently very costly to obtain would be Methane Hydrates. although the high cost, represents a potentially vast Methane resource for both the United States and the world. HOPE THIS HELPS
The correct option is c. (20 m) .
As the formula to calculate wavelength is :
wavelength = wavespeed / frequency
A radioactive isotope decays at a constant rate proportional to the number of radioactive atoms remaining. A simple way of describing the speed of decay is to see the time it takes for half of the atoms of a radioactive parent to decay and form the daughter element(s). This is called the half life.
Hope this helps