Answer:
the answer is D. Because the 1 atm pressure of water is 40.65 or 40.7.
 
        
             
        
        
        
1 mole=6.02 x 10^23 atoms so how many moles are there in 3.0 x 10^23 we will cross multiply, 1 x 3.0 x 10^23 / 6.02 x 10 ^23. Which will give us 0.498 moles. 
Hope this helped
        
             
        
        
        
The change in pressure over a given distance is defined as a pressure gradient. The strength of this pressure gradient determines how fast the wind moves from higher pressure toward lower pressure. A stronger pressure gradient will cause stronger winds, as shown in Figure 2. >> Balanced in the vertical by the force of gravity 
 
        
             
        
        
        
Answer:
20 km 
Explanation:
he walks 10 km + another 10 km so 20 :)