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 contai...