While ozone is a natural part of the Earth’s upper atmosphere, if it becomes concentrated in the lower atmosphere, it can potentially increase air pollution in areas where smog is a concern,
While ozone is a natural part of the Earth’s upper atmosphere, if it becomes concentrated in the lower atmosphere, it can potentially increase air pollution in areas where smog is a concern, (30)_______ can in turn impact the health of those living in these areas.
A. what
B. that
C. which
D. when