Final answer:
An indirect calorimetry system using a dilution technique determines the metabolic rate by measuring oxygen consumption and estimating energy expenditure. It can also determine the respiratory quotient (RQ) by assessing the ratio of carbon dioxide to oxygen in expired gases.Option C is the correct answer.
Step-by-step explanation:
An indirect calorimetry system that uses a dilution technique to mix a constant flow of entrained air with expired gas is primarily used to determine the metabolic rate. This is because the method allows for the measurement of oxygen consumption and can thus estimate the energy expenditure of an individual. The caloric value is calculated using the principle that when 1 litre of oxygen is utilized in the oxidation of organic nutrients, approximately 4.8 Kcal of heat is generated. Indirect calorimetry is a widely accepted method of measuring metabolic rate as it relates to oxygen utilization.
The respiratory quotient (RQ) is intimately linked with these measurements as it indicates the ratio of carbon dioxide produced to oxygen consumed. Different substrates such as carbohydrates, proteins, and fats will have different RQ values, but the primary goal of this system is to assess the metabolic rate. However, as part of the analysis, the RQ can be determined by calculating the ratio of produced CO₂ to consumed O₂ from the expired gas mixtures.