questions are to be answered

Okay like the headline states I have questions The first is about the Samsung propel and their many colors I am wondering about the difference between the hardware and software plus any bugs between the spectrum of colors for the phone •I state my case and question like that because I had the green version and every time I turned it off it turned back on The second one is about screen density because I have no Idea about screen density Thank you all for answering my questions