Despite the thermal stability of covalent bonds in physiological systems, some of these bonds are sensitive to energy input from external sources. The molecule can absorb heat from the environment

Despite the thermal stability of covalent bonds in physiological systems, some of these bonds are sensitive to energy input from external sources. The molecule can absorb heat from the environment without changing its chemical structure, as will occur when there is a local temperature increase. If the increase in energy is above kT (i.e., the entire environment has not increased its temperature), the molecule will come to thermal equilibrium with the environment around it, and return to its original energy state. Which one of the following physiological process is example to this?
Select one :
a. Absorbance of light by 11-cis-retinal.
b. Translucent to opaque conversion of egg whites after cooking.
C. Absorbance of light by melanın.
d. a & b
e. a & c
f.b&c
g. a, b & c