The internal energy and temperature of a system decrease (E E. The System and Work. The system is usually defined as the chemical reaction and the boundary is the container in which the reaction is run. In the course of the reaction, heat is either given off or absorbed by the system.
The Middle Ages began in the year 476 A.D. and ended around 1300 with the beginning of the Renaissance. The Middle Ages, also called the Medieval Period, began just after the fall of Rome and it dominated the European continent through the early 14th century. The Middle Ages filled a time period between the ending of a great reign and the beginning of a new era characterized by revitalization and cultural growth.
In European history, the Middle Ages were the period between approximately 1000 AD and 1400 AD. This practice was common throughout the Middle Ages. Middle age is the period in a person's life when they are no longer young but are not yet old. ...the onset of middle age.