What do you understand by AM range of radio communication? Can these waves pass through atmosphere?

Explanation

The electromagnetic waves of frequecny less
than 300 MHz (or wavelength 10 m or more) form
amplitude modulated range (i.e. A.M. range).
These waves more or less can pass through the
lower atmosphere of the earth. But these waves
are reflected back by the topmost layer of the
atmosphere, the ionosphere.