|
|
When blood is deoxygenated and flowing back to the heart through the veins, it is dark reddish-blue in color. Blood in the arteries that is oxygenated and flowing out to the body is bright red. Whereas arterial blood comes out in spurts, venous blood flows.
About 3.2 billion people, nearly half the world population, are at risk for malaria. In 2015, there are about 214 million malaria cases and an estimated 438,000 malaria deaths.
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.
To combat osteoporosis, changes in lifestyle and diet are recommended. At-risk patients should include 1,200 to 1,500 mg of calcium daily either via dietary means or with supplements.
If all the neurons in the human body were lined up, they would stretch more than 600 miles.
![Retinopathy. Illustration of a normal retina (left) and a diseased retina (right). The diseased reti](https://biology-forums.com/gallery/47/medium_14755_14_10_12_6_36_56_93981716.jpeg)
![People have seen patterns in the stars since ancient times.[5] This 1690 depiction of the constellat](https://biology-forums.com/gallery/47/medium_12359_26_01_13_3_44_40.png)