The average body temperature is
A. 98°F
B. 37 degree centigrade
C. 310.15 K
D. All of the above

Hint: Normal human body temperature, also known as normothermia or euthermia, is the typical temperature range found in humans.

Complete Answer:
- Temperature variation in the body can be caused by various reasons like fever, dizziness, vomiting, fast or slow heart rate, other medical emergencies, etc. Body temperature is kept in the normal range by thermoregulation, in which adjustment of temperature is done by the central nervous system.
- Humans can adapt to the varying climate conditions by physiological and behavioral mechanisms. During hot conditions, sweat glands secrete sweat that causes heat loss through evaporative cooling.
- The hair on the skin lies flat, preventing heat from being trapped by the layer of still air between the hairs. This is caused by tiny muscles under the surface of the skin called arrector pili muscles relaxing so that their attached hair follicles are not erect. These flat hairs increase the flow of air next to the skin increasing heat loss by convection.
- Arteriolar vasodilation occurs, which redirects blood into the superficial capillaries in the skin increasing heat loss by convection and conduction.
- During cold conditions, sweat production is reduced and heat is mainly lost through hands and feet, hence they are kept covered. The hair follicles become upright which acts as an insulating layer, trapping heat. Vasoconstriction occurs that prevents all heat loss from the blood. In extremely cold conditions, too much vasoconstriction causes numbness and pale skin.
- Maintaining body temperature is necessary so that the body can function properly and, to protect the body from dangerous conditions like hypothermia.
The reported range for normal body temperature is 36.5-37.5 degrees Celsius or 97.7- 99.5 degrees Fahrenheit.

Hence, the correct answer is option D, “all of the above” i.e. 37°C or 98°F or 310.15K.

Note: Human body temperature varies depending on the sex, age, time of day, exertion level, health status, what part of the body the measurement is taken at, state of consciousness (waking, sleeping, sedated), and emotions. It can vary a bit according to these factors but not too much.