Answer:
A. THEY ABSORBS RADIATION GIVEN OFF BY THE EARTH.
Step-by-step explanation:
Greenhouse gases are gases capable of absorbing and emitting infrared radiations in different wavelength range emitted by the earth. These gases include water vapor, carbon iv oxide, methane, ozone, chlorofluorocarbons, nitric oxide, hydrofluorocarbons. These gases contribute to the greenhouse effects and there actions are dependence on their respective characteristics, abundance in the atmosphere and the indirect effects it causes. Earth surfaces absorbs radiant energy from the sun and these radiations are reflected as light or reflected back to space as hear. Greenhouse gases are involved in absorbing and emitting these incoming energies in order to create a balance between the incoming and outgoing energies. This determines the temperature on the earth surface. The earth can be warm or cold depending on the direction the difference in this balance shifts. Without the greenhouse gases the average temperature of the earth will be lower than the expected temperature.