The higher the percentage of the active ingredient in a drug

Ammonia is the most active ingredient in cigarettes. It is claimed by the companies that it improves the flavor of the cigarette, but it is actually very addictive. It allows more nicotine to enter our bloodstream, which causes us to crave more than we want. However, nicotine is highly addictive in and of itself; the ammonia simply adds to the person's desire to smoke.

Explanation:

explanation: the line "to save the day, harry must get past a scary three-headed guard dog" from the summary best justifies the conclusion that harry potter and the sorcerer’s stone was influenced by ancient greek mythological literature. the three other choices had nothing to do with ancient greek literature - and the words "three-headed guard dog" are what makes that choice the correct answer.