Answer: Observation is essential in science. Scientists use observation to collect and record data, which enables them to construct and then test theories
Explanation:
You're right it's the oceans.. since most is salt water, the salt has to be boiled out
Characteristics of a medium wave. They are <span>Wavelengths in this band are long enough that radio waves are not blocked by buildings and hills and can propagate beyond the horizon following the curvature of the Earth; this is called the </span>ground wave<span>. Practical groundwave reception typically extends to 200–300 miles, with longer distances over terrain with higher </span>ground conductivity<span>, and greatest distances over salt water. Most broadcast stations use ground wave to cover their listening area. Hope this helps. :)</span>
They are different in wavelength.
