Why is the classification system of psychoactive drugs presented not a perfect system?

Groups of psychoactive drugs include stimulants, depressants, narcotics (opioids), hallucinogens, and marijuana (cannabis).

Explanation:

1. entire bag, then the entire bag of calories

2. the percent of fat would be the percent of fat from the serving size, added up to the entire bag of calories

3/4. the saturated fat would be on the bag label, but im pretty sure if you take the serving size and do the math to figure it out you could find out in total the fiber, saturated fat,etc..

5. no probably not