How many neurons are in the human brain?
The human brain contains about 86 billion neurons.
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- What is the photic sneeze reflex?
“Some people sneeze when they see bright light, a trait called the photic sneeze reflex.”
Reference: National Institutes of Health (NIH)
More from this shelf
How many scents can the human nose detect?
A 2014 study estimated that humans can tell apart about a trillion scents, though other scientists dispute the number.
How much energy does the brain use?
The brain makes up only about 2% of body weight but uses about 20% of the body's energy.