Without the Greenhouse Effect Operating in Our Atmosphere

Multiple Choice

Without the greenhouse effect operating in our atmosphere:

A) we would not have to worry about any warming problems in the future.
B) Earth would have an average temperature of -23 degrees Celsius.
C) the ice in the polar regions would have melted long ago.
D) the ozone layer would not be weakening.
E) the Earth would have become much more like Venus long ago.