At first it was mainly a hydrogen atmosphere. It's got changed dramatically on several occasions—for example, The nice Oxygenation Function 2.4 billion years back, enormously amplified oxygen inside the atmosphere from practically no oxygen to concentrations nearer to current day. Air may be the invisible combination of gases that surrounds https://airconditioningsystems36677.bloggactif.com/38810926/what-does-air-conditioning-systems-mean