Question

value: 3
which of the following layers of the atmosphere where the molecules are gravitationally bound to that body?
a. thermosphere
b. exosphere
c. stratosphere
d. mesosphere

Explanation:

The exosphere is the outermost layer of the atmosphere where gas molecules are gravitationally bound to the celestial body but are very sparse and can escape into space more easily compared to lower layers. The thermosphere, stratosphere, and mesosphere have more concentrated gas molecules and different characteristics, not matching the description of molecules being gravitationally bound in the way the exosphere does (with sparse, gravitationally - bound molecules that can still be considered part of the atmosphere's gravitational binding).

Answer:

b. Exosphere