A. One substance must dissolve in another
Einstein's energy mass equivalence relation say that if the whole given mass is converted to energy then it would be

where
m = mass in kg
c = speed of light in m/s
this is the origination of quantum physics and by this formula we can relate the dual nature of light and particle
So correct relation above will be

Answer:
Temperature : 92.9 F
Internal Energy change: -2.53 Btu/lbm
Explanation:
As
mh1=mh2
h1=h2
In table A-11 through 13E
p2=120Psi, h1= 41.79 Btu/lbm,
u1=41.49
So T1=90.49 F
P2=20Psi
h2=h1= 41.79 Btu/lbm
T2= -2.43F
u2= 38.96 Btu/lbm
T2-T1 = 92.9 F
u2-u1 = -2.53 Btu/lbm
The most important measure is awhips
The answer is A. Commensalism. <span>Commensalism, in ecology, is a class of relationships between two organisms where one organism benefits from the other without affecting it. This was the briefest answer from Wiki. Hope it helps, and sorry I'm late.</span>