One purpose may be to check for cancer. If abnormal cells are found, there might be something wrong...
Probably C. Because it says that it’s a part of the nervous system
Belly breathing
deep breathing
Being sedentary means you don't move around (stay in one place).
People who are sedentary could play video games at their computer all of the time, which means they stay up late.
Staying up late leads to sleep deprivation.
Thus, video gamers could have sleep deprivation.