harâ²borâ¢less, adj. harâ²borâ¢ous, adj. syn: harbor, port, haven refer to a shelter for ships. A harbor is a natural or an artificially constructed shelter and anchorage for ships: a fine harbor on the eastern coast.
Bright red bleeding during the menstrual cycle typically is nothing more than an indication of fresh blood being expelled along with the lining of the uterus. This normally occurs during the beginning of the cycle when the blood is freshest. As the cycle progresses, the blood may become darker and thicker.
Human blood is red because of the iron in the haemoglobin. This gives red blood cells their red colour. Veinous blood is much darker than arterial blood, and your teacher is right that oxygenated (arterial) blood is 'redder' than deoxygenated (veinous) blood. However, human blood is not blue. Some animals do have blue blood though.