Homosphere is a term used to describe the layers of the Earth's atmosphere where the composition remains relatively constant. This layer extends from the surface of the planet up to an altitude of around 80 kilometers. There are a few synonyms that can be used instead of homosphere, such as mixed atmosphere, standard atmosphere, or homogeneous atmosphere. The term mixed atmosphere is used because it is a combination of gases that are uniformly mixed, while standard atmosphere is used to describe the average composition of the Earth's atmosphere at sea level. A homogeneous atmosphere, on the other hand, means the composition remains relatively constant throughout the layer. These synonyms accurately represent the characteristics and properties of the homosphere.