« previous next »
« previous next »
 

Did you know?

The immune system needs 9.5 hours of sleep in total darkness to recharge completely.

Did you know?

Autoimmune diseases occur when the immune system destroys its own healthy tissues. When this occurs, white blood cells cannot distinguish between pathogens and normal cells.

Did you know?

Cyanide works by making the human body unable to use oxygen.

Did you know?

About 600,000 particles of skin are shed every hour by each human. If you live to age 70 years, you have shed 105 pounds of dead skin.

Did you know?

Eat fiber! A diet high in fiber can help lower cholesterol levels by as much as 10%.

Mammalian teeth Mammalian teeth
Snout and mouth of sand tiger shark, showing protruding teeth and small eyes Snout and mouth of sand tiger shark, showing protruding teeth and small eyes
Ears pulled back flat against the head with teeth bared and white of the eye showing, indicating ang Ears pulled back flat against the head with teeth bared and white of the eye showing, indicating ang
Erosion of palatal surfaces of maxillary teeth due to chronic vomiting. Erosion of palatal surfaces of maxillary teeth due to chronic vomiting.
Deciduous and permanent teeth Deciduous and permanent teeth
In the reaction C(s) + O2(g) CO2(g) carbon is __________. In the reaction C(s) + O2(g) CO2(g) carbon is __________.
Video: How to find out if a population is evolving?

For a complete list of videos, visit our video library