Answer:
Your answer should be Cooled Air
Explanation:
 
        
             
        
        
        
The correct answer is: 
<span>C)	The actual frequency of the siren does not change despite appearances.
In fact, Bob will observe an increase in the apparent frequency as the emergency vehicle approaches him, while Jill will observe a decrease in the apparent frequency as the emergency vehicle moves away from him, because of the Doppler effect (the relative velocity between the observer and the source of the sound is changing), but this effect involves the apparent frequency, while the real frequency of the siren will remain the same.</span>
        
                    
             
        
        
        
I believe the sun is the primary source of energy for Earth's weather system. The sun is the primary energy source for Earth's climate system which is the first set of essential principles of climate sciences. Additionally, it is the primary source that drives all weather events, including precipitation, hurricane and tornadoes. The sun drives the hydrologic cycle, and makes life on Earth possible. 
        
             
        
        
        
The displacement is zero. The most important concept to understand is the difference between displacement and total distance traveled. Total distance traveled would be tracking the length of the entire path the ant walked for the whole time (4.26m x 2). Displacement is how far from a designated origin (here, the food source) the ant ended up at the end of the time. Mathematically, the ant walked 4.26m from food source to nest (+4.26m) and then walked from the nest to food source (-4.26m), so the net displacement is [+4.26] + [-4.26] = 0m.