Medical Definition of Red blood cells. Red blood cells: The blood cells that carry oxygen. Red cells contain hemoglobin and it is the hemoglobin which permits them to transport oxygen (and carbon dioxide). Hemoglobin, aside from being a transport molecule, is a pigment. It gives the cells their red color (and their name).
Alexander Milne Calder (August 23, 1846 â June 4, 1923) was a Scottish American sculptor best known for the architectural sculpture of Philadelphia City Hall. Both his son, Alexander Stirling Calder, and grandson, Alexander Sandy Calder, became significant sculptors in the 20th century.
Alexander III of Macedonia was born in 356 BCE to King Phillip II of Macedonia and his wife, Olympias, princess of Epirus. As part of his royal upbringing, he was tutored by the philosopher Aristotle. Many of Aristotle's teachings stayed with Alexander and guided him throughout his life.