The simple answer is - imagine someone who is working out regularly and someone who isn't.
The person who work out regularly may have more muscles than the other one, but at the same time, he has a worse genetic predisposition for muscle gain. The guy who does not work out on the other hand, has a better genetic predisposition for muscle gain, yet does not work out.
This is how our environment can influence muscle structure.
The difference between vitamins and minerals has to do with their chemical structure. Vitamins can be broken down, but minerals are inorganic and cannot be broken into smaller chemical units.
