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.
It's the troposphere because : The troposphere contains 75 per cent of the atmosphere's gas. It also holds huge amounts of dust and water vapor, and is often dense with clouds and mist. Air pressure is greatest in the troposphere, because gravity pulls the atmosphere towards the Earth, squeezing most of its weight into this lowest layer. It's the troposphere because : The troposphere contains 75 per cent of the atmosphere's gas.