4.Explain what must be true of component waves for reinforcement or interference to occur.

The component of waves must have same frequency and phase.

Explanation:

when the component of waves vibrate at the same rate and attain maximum point at the same time, reinforcement of the waves amplitude occur to cause a constructive interference.However, when the two waves are out of phase where one is at minimum when the other is at maximum a destructive interference happens.

its c its is a mixture of gases

c)as speed changes, wavelength and frequency change.

everything changes!