Final answer:
The statement is true as the heterosphere has a layered structure due to gravitational separation, whereas the homosphere contains a well-mixed combination of atmospheric gases due to turbulent mixing.
Step-by-step explanation:
The statement that the heterosphere has a layered structure, whereas the homosphere occurs as an even mixture of gases is true. The heterosphere starts above the homosphere and continues to the outer limits of the Earth's atmosphere. It is characterized by its layered structure due to the gravitational separation of gases at various altitudes, with lighter gases like hydrogen and helium found at higher altitudes.
On the contrary, the homosphere includes the troposphere, stratosphere, mesosphere, and the lowest part of the thermosphere where gases are well-mixed due to the turbulent mixing caused by weather phenomena. This layer extends up to about 80 kilometers (50 miles) from the Earth's surface. Beyond this region, the heterosphere's layers include the remaining part of the thermosphere and the exosphere, where the atmospheric gases start to thin out into space.