Starting in the late 1970s and. continuing for decades, an increasing amount of the. protective layer of stratospheric ozone above Antarctica. would disappear during late September and October, cre-. ating what is popularly known as the ozone hole.
A battalion is a military unit. The use of the term battalion varies by nationality and branch of service. Typically a battalion consists of 300 to 800 soldiers and is divided into a number of companies. A battalion is typically commanded by a lieutenant colonel. In some countries the word battalion is associated with the infantry. The term was first used in Italian as battaglione no later than the 16th century.
A company typically has 100 to 200 soldiers, and a battalion is a combat unit of 500 to 800 soldiers. Three to five battalions, approximately 1,500 to 4,000 soldiers, comprise a brigade. The size of a division varies from about 10,000 to 18,000 soldiers, and most divisions have three or more brigades of roughly equal size. A corps, which consists of two or more divisions and support troops, normally has from 50,000 to 100,000 soldiers. Artillery groups are known as batteries, and groups of cavalry are called troops. The division is the basic fighting unit of many armies.