Which pair correctly matches a heat unit with its system?

Which pair correctly matches a heat unit with its system?

• A. BTU — metric system
• B. Calorie — English system
• C. Calorie — metric system
• D. Joule — English system

Answer: (C)

Heat units are tied to the system they come from. The calorie is a unit that sits with the metric (SI-friendly) tradition, defined using grams and degrees Celsius. That makes it a metric-system unit of heat. In contrast, the English system uses the BTU for heat, and the Joule is the SI (metric) unit—not an English unit. So the pairing of calorie with the metric system is the correct one. (Note: in nutrition, people often use kilocalories, but they’re still based on the same calorie concept in metric terms.)

Heat units are tied to the system they come from. The calorie is a unit that sits with the metric (SI-friendly) tradition, defined using grams and degrees Celsius. That makes it a metric-system unit of heat. In contrast, the English system uses the BTU for heat, and the Joule is the SI (metric) unit—not an English unit. So the pairing of calorie with the metric system is the correct one. (Note: in nutrition, people often use kilocalories, but they’re still based on the same calorie concept in metric terms.)