Blood is the life giving fluid that delivers oxygen to the cells of the body. It is a specialized type of connective tissue that consists of red blood cells, platelets, and white blood cells suspended in a liquid plasma matrix. Did you know that blood accounts for about 8 percent of your body weight or that blood contains small amounts of gold? While humans have red colored blood, other organisms have blood of varying colors. Crustaceans, spiders, squid, octopuses, and some arthropods have blue blood. Some types of worms and leeches have green blood. Some species of marine worms have violet blood. Insects, including beetles and butterflies, have colorless or pale-yellowish blood. The color of blood is determined by the type of respiratory pigment used to transport oxygen via the circulatory system to cells. The respiratory pigment in humans is a protein called hemoglobin found in red blood cells. Your body contains about a gallon of blood. The adul...
Australia's Great Barrier Reef is considered to be the world's largest reef system. It is made up of over 2,900 individual reefs, 900 islands and covers an area of 133,000 square miles (344,400 sq km). It is also one of the Seven Natural Wonders of the World, a UNESCO World Heritage Site and it is the world's biggest structure made out of living species. The Great Barrier Reef is also unique in that it is the only living organism that can be seen from space. The Great Barrier Reef is located in the Coral Sea. It is off the northeast coast of Australia's state of Queensland. The reef itself stretches over 1,600 miles (2,600 km) and most of it is between 9 and 93 miles (15 and 150 km) from shore. In places the reef is up to 40 miles (65 km) wide. The reef also includes Murray Island. Geographically, the Great Barrier Reef stretches from Torres Strait in the north to the area between Lady Elliot and Fraser Islands in the south. Much of the Great Barrier Reef is protected...