I would say C is the most correct. 
In D it depends on what water source you're using. Let's say it is a waterfall, then the source of the water (melting ice or a lake) may disappear in the future. 
If you're using underwater "windmills" placed in the ocean, then you would expect it to last a while as the ocean will not disappear in the near future. 
        
             
        
        
        
Sand dunes would be created due to the mixture falling on each other
x
        
                    
             
        
        
        
Answer:
1.8 × 10² cal
Explanation:
When 0.32 g of a walnut is burned, the heat released is absorbed by water and used to raise its temperature. We can calculate this heat (Q) using the following expression.
Q = c × m × ΔT
where,
c: specific heat capacity of water
m: mass of water
ΔT: change in the temperature
Considering the density of water is 1 g/mL, 58.1 mL = 58.1 g.
Q = c × m × ΔT
Q = (1 cal/g.°C) × 58.1 g × 3.1°C
Q = 1.8 × 10² cal
 
        
             
        
        
        
Answer:
radius = 156 pm
Explanation:
The relation between radius and edge length of unit cell of BCC is
r=a /4
/4
Given
a = 360 pm
Therefore
r = r = radius = 360 /4= 155.88 pm
/4= 155.88 pm
Or
156 pm
 
        
             
        
        
        
<h3>
Answer:</h3>
 = 5.79 × 10^19 molecules 
<h3>
Explanation:</h3>
The molar mass of the compound is 312 g/mol 
Mass of the compound is 30.0 mg equivalent to 0.030 g (1 g = 1000 mg)
We are required to calculate the number of molecules present 
We will use the following steps;
<h3>Step 1: Calculate the number of moles of the compound </h3>

Therefore;
Moles of the compound will be; 

       = 9.615 × 10⁻5 mole 
<h3>Step 2: Calculate the number of molecules present </h3>
Using the Avogadro's constant, 6.022 × 10^23 
1 mole of a compound contains 6.022 × 10^23  molecules 
Therefore;
9.615 × 10⁻5 moles of the compound will have ;
 = 9.615 × 10⁻5 moles × 6.022 × 10^23  molecules 
 = 5.79 × 10^19 molecules 
Therefore the compound contains 5.79 × 10^19 molecules