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Thats just one. Like athos said, do some research. I've already done years of research on my own as well as taken many collegiate classes involving everything from kinesiology to human physiology.
Also, yes everyone is different and everyone has different bodyfat percentages, but when you start dipping below 6% you start messing with a lot of bodily function's and the bodies homeostasis. As for bodybuilding, diuretics effect potassium and electrolyte balances. That is why they are so dangerous, not bc of low body fat. Someone who is obese who takes diuretics can harm or even kill themselves the same way a bodybuilder with body fat below 6% can.