A blood transfusion is a safe, common procedure in which blood is given to you through an intravenous (IV) line in one of your blood vessels. Blood transfusions are done to replace blood lost during surgery or due to a serious injury. A transfusion also may be done if your body can't make blood properly because of an illness. During a blood transfusion, a small needle is used to insert an IV line into one of your blood vessels. Through this line, you receive healthy blood. The procedure usually takes 1 to 4 hours, depending on how much blood you need. Blood transfusions are very common.
1 The roots of the ancient mountain range that now lies at the bottom of the Grand Canyon were formed about 1.7 billion years ago. 2  There is then an unconformity of about 450 million year in which the rocks are missing. 3  At 1.25 billion years ago the first sedimentary layer, the Bass Formation, was laid down.
The Grand Canyon is 277 miles (446 km) long, up to 18 miles (29 km) wide and attains a depth of over a mile (6,093 feet or 1,857 meters).he great depth of the Grand Canyon and especially the height of its strata (most of which formed below sea level) can be attributed to 5â10 thousand feet (1,500 to 3,000 m) of uplift of the Colorado Plateau, starting about 65M years ago (during the Laramide Orogeny).