When you exercise, your body produces something called endorphins (it's sort of like morphine), and it makes your body feel less pain and make you feel more happy. In this case, the endorphins combat your stress and make you feel better mentally.
I will try to help you with your work just tell me what you need help with and i will try to help
In this situation you should report what you have seen, get an adult to deal with the problem. You would not want to interfere yourself, just because it could be hazardous.
As for the partner question, just find anyone else to answer and write what they say
Try understanding from there point of view, but they should also understand where you’re coming from. if you live with them, you follow there rules. if you don’t live with them, you don’t need to.