Your answer is A
Offering your friends something unhealthy or unsafe is considered peer pressure
Diet and exercise would be things to control calories. But mainly your diet.
It's called drug abuse
It bolsters one's physical state if it create an abnormal impact to one's body by stopping the usage. For example, some one who suddenly stopped taking heroine will experience an excruciating pain in their body
It bolster one's psychological state if the drug have no medication effect to their body, but they somehow still crave it
Most likely c. variable since it says a factor that "can vary"
a, because exercise doesn't just aid the prevention of certain diseases, it helps prevent many diseases. i would've chosen d if it wasn't so specific but a is the correct answer.