If red light is shined on a population of red walking beans then they would not be as red as when started because they need light to survive and red light is present but they reflect it until they need it to survive.
Mutations that naturally occur can change phenotype and if it is beneficial to the species then it will be past on if it is no then it will die before passing it on.
Alright, so mass is a property of a physical body. During physical changes, such as acceleration, force, etc, the mass stays the same since we are not affecting its physical shape, just where it is physics wise. So yeah mass is conserved during a physical change.
(This is very confusing I'm bad at explaining things sorry)
General transcription factors are involved in the formation of a preinitiation complex. The most common are abbreviated as TFIIA, TFIIB, TFIID, TFIIE, TFIIF, and TFIIH
Natrual variations i think