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Cancer has been around as long as humankind, but only in the second half of the twentieth century did the number of cancer cases explode.
Each year in the United States, there are approximately six million pregnancies. This means that at any one time, about 4% of women in the United States are pregnant.
Asthma attacks and symptoms usually get started by specific triggers (such as viruses, allergies, gases, and air particles). You should talk to your doctor about these triggers and find ways to avoid or get rid of them.
The lipid bilayer is made of phospholipids. They are arranged in a double layer because one of their ends is attracted to water while the other is repelled by water.
When blood is exposed to air, it clots. Heparin allows the blood to come in direct contact with air without clotting.