Medicinal and misused drugs
A drug is any substance taken into the body that changes its chemical reactions. Antibiotics kill or stop the growth of bacteria but have no effect on viruses. Overuse leads to antibiotic resistance: random mutations make some bacteria resistant; they survive and multiply (natural selection), e.g. MRSA. Reduce it by prescribing antibiotics only when needed and finishing the course. Misused drugs harm the body: alcohol (depressant, liver damage), heroin (depressant, highly addictive, infection from shared needles), nicotine (addictive), anabolic steroids (muscle growth, banned in sport).
≈ 30 min