The body must produce the liquid part of blood, called plasma, and the cells that float in it.
Through the early 1600s, physicians believed there were two kinds of blood, one made by the liver and one by the heart...
Although Everest had first been climbed in 1953, this was the first successful ascent to be made without supplemental oxygen.
What keeps penguin's feet from freezing? Penguins' feet don't freeze because of the blood circulating in them.
When fluid blocks the passage of oxygen into the lungs, the resulting suffocation is known as drowning, whether or not the person is submerged in water.
Oddly enough, a solution of 70% alcohol, that is, rubbing alcohol, is a more effective antiseptic than 100% alcohol. Another case of where more is not better.
They prowl in the dark, soar through starlit skies... they are vampire bats and they're looking for blood!
There's mounting evidence that long stretches of inactivity are not good for you, even if you're not overweight and seem basically healthy.
The bacteria take nitrogen out of the air and make it available to other living organisms in an amazing process.