Fact 1: Afire requires oxygen to burn. Fact 2: Oxygen-enriched air is a fire hazard because the burning rate of combustible materials is increased. Given the two facts above, how do you increase the burn rate?
Choices: (1). an electric stove; (2). exercise; (3). burn wet materials; (4). friction; (5). add more oxygen; (6). decrease amount of fuel; (7). a hydraulic system; (8). decrease the oxygen;
Answer:
(5).