For the first question, choloroplasts. These are the building blocks of any plant, whether flower or fruit.Choroplasts are simply cyanobacteria, that entered into endosymbiosis with some other early organism. They started using photosynthesis: 6H2O+6CO2+light=C6 H12O6+6O2. And now they live among us, being green.
Why not? Always, that is the question that people face. Why should we not? Genetics can, if we wanted them to, make all plants pink. Why not? Why not? I think, and mind you this is only part of the answer, why? Why should we tamper with the genetics of plants when we could sit by the computer desk and write stories?
'Tis folly, then, to make plants pink. I would much rather make them red, in any case. my favourite colour. So... is that the answer you sesire for the latter question? If not, you must be satasfied, because I don't deign to waste too much time on the complaints of normal people like you. Unless, of course you will pour me another cognac?