Choose your answer from: 1. oxgen; 2. influenza; 3. viruses; 4. disease; 5. chickenpox; 6. bacteria; 7. cooking food; 8. contracting itchiness;
Given those answer options, answer the question: Fact 1: Bacteria cause food poisoning. Fact 2: Food poisoning is a serious illness. Given the two facts above, what causes serious illness?
A:
6.