What is the largest organ of the human body?
AnswerThe skin
The skin is the body's largest organ, covering and protecting everything inside.
Health · Facts & stats
Wellness facts & stats
7 fact-checked facts about wellness and the body, each with the reason behind it. 5 more are in today's round and join this page after it closes.
The basics
Heart rate is usually measured in which unit?
AnswerBeats per minute
Heart rate counts how many times the heart beats in one minute.
Going deeper
Roughly what share of an adult human's body weight is water?
AnswerAbout 60%
Water makes up roughly 60% of an adult's body weight, varying with age and body composition.
The body's circadian rhythm runs on a cycle of about how long?
Answer24 hours
'Circadian' comes from Latin circa diem, 'about a day', describing roughly 24-hour body cycles.
In sleep science, what does REM stand for?
AnswerRapid eye movement
REM sleep is named for the quick eye movements during this stage, when vivid dreaming is common.
Expert level
Which hormone released by the adrenal glands is often called the stress hormone?
AnswerCortisol
Cortisol is released by the adrenal glands and helps the body respond to stress.
Which brain region acts as the body's master circadian clock?
AnswerThe suprachiasmatic nucleus
The suprachiasmatic nucleus in the hypothalamus uses light signals from the eyes to set daily rhythms.
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