Where Is Most Of The Body's Serotonin Produced? Heart Gastrointestinal tract Lungs Bones Did You Know! Changes in the skin can occasionally provide clues about problems elsewhere in the body….

What Is One Reason Yawning May Be Contagious? Your lungs detect someone else's breathing Seeing yawning can trigger the behavior Your body senses another person's oxygen level Yawning is caused…

Which Body Structure Continues Changing Throughout Adulthood? Nose Eyeball Skull Kneecap Did You Know! Some skin disorders can follow invisible “lines” across the body. Certain skin conditions can develop along…

Why Can Standing Up Very Quickly Sometimes Make You Feel Dizzy? Your brain temporarily shrinks Your lungs stop absorbing oxygen Your ears temporarily stop working Blood pressure can briefly fall…

Which Action Uses Muscles Even Though You May Barely Notice You're Doing It? Growing hair Blinking Growing fingernails Producing red blood cells Did You Know! Glaucoma can damage vision before…

What Unusual Effect Can Holding Your Nose Have While Eating Food may seem less flavorful Food becomes physically sweeter Your taste buds temporarily multiply Salty foods become smoother Did You…

What Unusual Ability Does Your Stomach Lining Have? It glows in darkness It never contains bacteria It stops working while you sleep It regularly renews itself Did You Know! Some…

What Usually Happens To Your Heart Rate When You take A Slow, Deep Breath In? It stops briefly It tends to increase slightly It always drops by half It remains…

Why Does Your Nose Sometimes Run When you Eat Spicy Food? Your body thinks you're sick Spicy compounds stimulate nerves in the nose Your stomach produces extra water Your blood…