True or False Human Body Facts

Explore true or false facts about the human body, senses, sleep, the brain, blood and bones. Read a statement, then open its answer and explanation

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Late in pregnancy, a baby already recognizes its mother's voice
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True
From about 33 weeks of pregnancy, studies show a fetus reacts differently to its mother's voice than to a stranger's
Source: en.wikipedia.org
The so-called funny bone is really a nerve at the elbow
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True
Knocking it presses the ulnar nerve against the elbow bone, which sends that tingling jolt through the arm
Source: en.wikipedia.org
Many people who lose a limb still feel it as if it were there
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True
Studies find that 50% to 80% of amputees report sensations from a limb that is no longer there
Source: en.wikipedia.org
Swallowed chewing gum usually stays in your stomach for about 7 years
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False
Gum moves through the digestive system like other food and usually passes within days, even though it is not digested
Source: scientificamerican.com
A newborn baby has more bones than an adult does
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True
Babies start with about 270 bones, and many fuse as they grow, leaving 206 in an adult
Source: en.wikipedia.org
On average, men have one rib fewer than women, 23 against 24
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False
Men and women normally both have 12 pairs of ribs, a count the anatomist Vesalius confirmed in the 1500s
Source: en.wikipedia.org
Identical twins have exactly the same fingerprints
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False
Twins share their DNA, but conditions in the womb shape the fine ridges, so their prints differ
Source: en.wikipedia.org
Blue eyes get their color from scattered light, not blue pigment
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True
Blue eyes have little melanin, and the iris scatters light much as the sky does, so no blue pigment is involved
Source: en.wikipedia.org
Each taste has its own tongue zone, with sweet at the tip and bitter at the back
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False
Every taste can be sensed on all parts of the tongue, and the map came from a misread German study of 1901
Source: en.wikipedia.org
Cells from a baby can stay in its mother's body for decades
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True
Fetal cells cross the placenta, and male DNA has been found in women decades after they gave birth to sons
Source: pmc.ncbi.nlm.nih.gov
You breathe mostly through one nostril, and the side switches every few hours
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True
Swelling tissue inside the nose narrows one side and opens the other, and in one study the cycle averaged about 2 hours
Source: journals.plos.org
Your finger muscles sit in the palm and forearm, not in the fingers
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True
Tendons pull the finger bones from muscles in the forearm and palm, so the fingers hold no working muscles of their own
Source: en.wikipedia.org
Every human body is slightly radioactive from natural elements it contains
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True
Potassium-40 and carbon-14 taken in with food and air decay inside you, thousands of times every second
Source: hps.org
The gallbladder, under the liver, makes the bile that breaks down fats
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False
The liver makes bile, and the gallbladder only stores it between meals and releases it into the small intestine
Source: niddk.nih.gov
Most of your body heat escapes through your head in cold weather
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False
The head loses no more than about 10% of body heat, and in old tests it stood out only because it was the uncovered part
Source: medicine.iu.edu
The lub-dub sound of a heartbeat is the heart muscle squeezing and relaxing
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False
The sounds come from the heart valves snapping shut, first the valves between chambers, then the valves to the arteries
Source: en.wikipedia.org
Sleepwalking usually happens during dream-filled REM sleep
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False
It occurs in deep non-REM sleep, when the muscles are not paralyzed the way they are in REM sleep
Source: en.wikipedia.org
Your body gives off a faint glow of visible light too dim to see
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True
Cameras that detect single photons show the body emits light about 1000 times weaker than the naked eye can sense
Source: journals.plos.org
Your brain makes more serotonin than your gut does
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False
About 90% of the body's serotonin is made by cells in the gut, and only a small share is found in the brain
Source: en.wikipedia.org
Your arteries hold more of your blood than your veins do
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False
At any moment nearly 70% of the body's blood is in the veins, and far less is in the arteries
Source: en.wikipedia.org

True or False Human Body Facts

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