|
|
In the ancient and medieval periods, dysentery killed about ? of all babies before they reach 12 months of age. The disease was transferred through contaminated drinking water, because there was no way to adequately dispose of sewage, which contaminated the water.
The Babylonians wrote numbers in a system that used 60 as the base value rather than the number 10. They did not have a symbol for "zero."
Most strokes are caused when blood clots move to a blood vessel in the brain and block blood flow to that area. Thrombolytic therapy can be used to dissolve the clot quickly. If given within 3 hours of the first stroke symptoms, this therapy can help limit stroke damage and disability.
A good example of polar molecules can be understood when trying to make a cake. If water and oil are required, they will not mix together. If you put them into a measuring cup, the oil will rise to the top while the water remains on the bottom.
Human neurons are so small that they require a microscope in order to be seen. However, some neurons can be up to 3 feet long, such as those that extend from the spinal cord to the toes.