Answer: The symbol representing the result of a gas expanding against a constant pressure is W
Explanation:
According to first law of thermodynamics, energy can neither be destroyed nor created but rather transferred to one place to another and converted to and from other energy forms.
The mathematical form of first law of thermodynamics is:

where
= change in internal energy
q = heat absorbed or released
W = work 
P = pressure
= volume change
Thus the changes in heat or work leads to change in internal energy.
It produces Heat Energy that can be used to drive steam turbines to generate Electricity.
The biggest barrier to the use of renewable energy in the United States is the Citizen opposition to negative environmental impact.
So, the answer is B.