Brass is an alloy of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties. + 18 others found this useful. Jack Bakhet. Edit. Share to: Chrishan Silva. 509,209 Contributions. I'm an undergraduate in Physical Sciences stream.
1 Two gases make up the bulk of the earth's atmosphere: nitrogen (), which comprises 78% of the atmosphere, and oxygen (), which accounts for 21%. 2  Various trace gases make up the remainder. 3  Based on temperature, the atmosphere is divided into four layers: the troposphere, stratosphere, mesosphere, and thermosphere.
Earth's atmosphere is the layer of gases around the Earth. The atmosphere is held in place by Earth's gravity. It is made up mainly of nitrogen (78.1%). It also has plentiful oxygen (20.9%) and small amounts of argon (0.9%), carbon dioxide (~ 0.035%), water vapor, and other gases.