Final answer:
The most common drugs used by adolescents are tobacco and alcohol, due to their wide availability and the significant health risks they pose.
Step-by-step explanation:
The two most common drugs used by adolescents are tobacco and alcohol. Alcohol is widely recognized as a pervasive depressant and a major concern among teenagers and young adults due to its potential to cause a series of health complications at different levels of consumption, from mild sedation and poor coordination to severe respiratory depression, comas, or even death.
Tobacco, often consumed through cigarettes or vaping, remains prevalent among middle and high school students and constitutes a significant health risk due to its addictive nature and the consequences associated with nicotine.