Rhinos existed back in prehistoric times and when flourished in thousands, moving into diverse habitats across Africa, Asia, Europe and North America. Today, due to poaching and habitat loss, few remain. Since 1970 alone, the rhinoceros population has declined by approximately 90 percent, in line with the American Wildlife Foundation. As of 2010, you can find five type of rhinos totaling approximately 24,500 within the wild and 1,250 in captivity, reports the International Union for Conservation of Nature (IUCN). The White Rhino is under threat of extinction and also the other four species are saved to the verge of extinction. The five remaining species are: The main function of human red blood cells or erythrocytes is usually to carry oxygen to several areas of the body. Their natural beautiful red colors comes from a biomolecule called hemoglobin which binds oxygen and occupies the cytoplasm of the cell. Unlike most human cells, red blood cells don't have nuclei or other organelles (the components or subunits of many cells). Their biconcave appearance can clearly be seen with this image which was captured using a scanning electron microscope (SEM). Looking like doughnuts without holes, they're flat and depressed inside center and also have a dumbbell-shaped cross-section. This unusual form is very important for his or her function because it is great for their smooth passage through minor and major veins. Korean Ginseng has been used in China as a sexual tonic for about 7000 decades. Deep, relaxed breathing relaxes stressed- out body and oxygenates the blood. The Internet might be rife with virus alerts, phishing scams, worms and trojans, however these threats happen to be slow to infect our mobile phones. They can in principle (there's been a worm on jailbroken iPhones), but since yet Android phones never have suffered another panic attack. There have been some scare stories about potential exploits in third-party software for Android mobile phones, but that is still the main topic of much debate.