You are presented with the quiz "what results in higher levels of uv radiation reaching the place birds and trees live?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "ozone depletion results in higher levels of UV radiation reaching Earth" and "birds live on Earth, trees live on Earth". 

So, what's the best answer to the question?


 

    ozone depletion       