98.6°F is used as the standard average body temperature because it is considered the normal temperature of a healthy human body when measured orally. This value was established through research by a German physician, Carl Wunderlich, in the 19th century. It represents a balance where the body functions optimally. However, normal body temperature can vary slightly from person to person and can be influenced by factors like the time of day or physical activity.

This question related to Chapter 7 Science Curiosity Class 6th NCERT.
From the Chapter 7. Temperature and its Measurement.
Give answer according to your understanding.