« previous next »
« previous next »
 

Did you know?

The human body produces and destroys 15 million blood cells every second.

Did you know?

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

Did you know?

The Romans did not use numerals to indicate fractions but instead used words to indicate parts of a whole.

Did you know?

Pope Sylvester II tried to introduce Arabic numbers into Europe between the years 999 and 1003, but their use did not catch on for a few more centuries, and Roman numerals continued to be the primary number system.

Did you know?

Malaria mortality rates are falling. Increased malaria prevention and control measures have greatly improved these rates. Since 2000, malaria mortality rates have fallen globally by 60% among all age groups, and by 65% among children under age 5.

An example of external fertilization. An example of external fertilization.
Internal view of the heart with aorta, vena cava, and pulmonary arteries and veins. Internal view of the heart with aorta, vena cava, and pulmonary arteries and veins.
Internal anatomy of a turtle Internal anatomy of a turtle
This internal bypass passage in the thermostat housing directs cold coolant to the water pump. This internal bypass passage in the thermostat housing directs cold coolant to the water pump.
Work is done by an external agent Work is done by an external agent
Internal structures of the female pelvis for landmarks Internal structures of the female pelvis for landmarks
Video: Primary Active Transport - electrochemical gradient and ion transport / water movement

For a complete list of videos, visit our video library