For which of the following purposes does the body burn calories?

The body burns calories primarily for several essential functions, including Basil Metabolic Rate (BMR), digestion, and exercise, all encapsulated in the correct answer.

BMR represents the number of calories burned while the body is at rest, maintaining life-sustaining processes such as breathing, circulation, and cell production. This basal energy expenditure is crucial because even when just sitting still, the body requires energy to function.

Digestion also contributes to calorie expenditure. The process of breaking down food and absorbing nutrients requires energy, known as the thermic effect of food, which accounts for a percentage of daily calorie consumption.

Lastly, exercise contributes significantly to calorie burning, as physical activity increases energy expenditure to support muscular activity and various bodily movements.

The other options do not directly relate to calorie burning in the same fundamental way. While prevention of illness and detoxification are important health functions, they are not primary reasons for caloric expenditure. Social engagement, while beneficial for mental health, does not inherently require the burning of calories as a primary function. Thus, focusing on BMR, digestion, and exercise provides a complete understanding of why the body burns calories.