Output is measured by body what?

Output is primarily measured by fluid when considering bodily functions, especially in healthcare contexts. This measurement is crucial for monitoring a patient's health status and ensuring their body's fluid balance is maintained. For instance, measuring urine output gives important insights into kidney function, hydration levels, and overall health.

While weight and temperature can also provide valuable information about a person's condition, they do not focus on the body's output in the same way that fluid measurement does. Weight typically reflects a combination of body composition (muscles, fat, water, etc.) and does not directly indicate the metabolism or loss of fluids, whereas temperature is vital for assessing metabolic activity or infections but does not pertain to output measurement. Therefore, fluid measurement is specifically aligned with tracking outputs, making it the most relevant choice in this context.