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 Von Humboldt (portrait) was born in Berlin, Germany in 1769. His father, who was an army officer, died when he was nine years old so he and his older brother Wilhelm were raised by their cold and distant mother. Tutors provided their early education, which was grounded in languages and mathematics.