Which of the following statement is/are correct

Options

A. The main gases within the Earth's exosphere are the lightest gases, mainly hydrogen, with some helium, carbon dioxide, and atomic oxygen near the exobase.
B. The exosphere is the last layer before space.
C. Since there is no clear boundary with space and the exosphere, the exosphere is sometimes used synonymously with outer space.
D. All the above

Answer

D

Explanation

The main gases within the Earth's exosphere are the lightest gases, mainly hydrogen, with some helium, carbon dioxide, and atomic oxygen near the exobase. 2. The exosphere is the last layer before space. 3. Since there is no clear boundary with space and the exosphere, the exosphere is sometimes used synonymously with outer space. These all are correct.