<span>As a sound source gets closer, both the volume and the pitch of the sound increased. Then, as the sound source passed by you, both the volume and the pitch of the sound decreased.
Hope this helps</span>
Answer:

Explanation:
v = Velocity of the breeze = 4 m/s
w = Width of the valley = 5000 m
h = Height of the valley = 1000 m
Volumetric flow rate is given by

= Mass flow rate of pollutant = 25 g/s = 
Concentration is given by

The steady state concentration of pollutants in the valley, is
.
The answers To your question is c
<span>Water in the oceans may become fresh water available to humans through the processes of evaporation, condensation and precipitation.
In these processes, water is heated to a very high temperature until it evaporates in order to kill the germs and remove the salts which remains after water evaporation. The next step in condensing the water vapor (which is now fresh) and precipitating this vapor to be used by humans.</span>