|
|
Giardia is one of the most common intestinal parasites worldwide, and infects up to 20% of the world population, mostly in poorer countries with inadequate sanitation. Infections are most common in children, though chronic Giardia is more common in adults.
People with high total cholesterol have about two times the risk for heart disease as people with ideal levels.
Vaccines cause herd immunity. If the majority of people in a community have been vaccinated against a disease, an unvaccinated person is less likely to get the disease since others are less likely to become sick from it and spread the disease.
Multiple sclerosis is a condition wherein the body's nervous system is weakened by an autoimmune reaction that attacks the myelin sheaths of neurons.
The average adult has about 21 square feet of skin.
![The 2012 U.S. presidential campaign rang with “get tough” cries to end Iran’s nuclear capacity and c](https://biology-forums.com/gallery/47/medium_262797_12_08_15_1_33_46_22174277.png)
![When the United States gets stuck over a controversial issue—usually something a divided Congress ca](https://biology-forums.com/gallery/47/medium_262797_12_08_15_1_37_16_22180672.png)