Light waves reflect off of certain things and absorb into others, but these things depend on the color of the wave. Your eyes don't see light that is absorbed, but rather reflected off of the surface of the object. For example, a white T-Shirt is white because all light is reflected, as an orange T-Shirt is orange because red and yellow light waves are both reflected.
A) Equilibrium :)
Equilibrium is the equal balance of molecules between two areas.
The answer is 1). Two Tt parent can produce T and t for 50% separately. So for the result, TT has the probability of 50%*50%=25%. The same for tt. And Tt is 1-0.25-0.25=50%.