Select all of the statements that correctly describe mechanical waves. A. They can change speed.
B. Microwaves are an example of them.
C. They can travel through air and water.
D. Ocean waves are an example of them.
E. They can travel through a complete vacuum.
F. They can travel faster than the speed of light.

The ideal gas model is valid if which of the following conditions is true? the gas density is low. the gas density is high. the temperature is low. the temperature is high. the gas density and the temperature are low. the gas density and the temperature are high. the gas density is high and the temperature is low. the gas density is low and the temperature is high.