I think it's D. Sry if you get it wrong though
The light ray bends toward the normal when entering water
The amount of water on the planet is fixed; it neither increases or decreases. Glaciers are sheets of moving ice. This water to form these extensive sheets must come from somewhere. The water comes from the most extensive store on the planet; the oceans. Ice Ages always corresponds to periods of low sea level because much of the ocean water is is land locked as glaciers.
It will take 15 years for Della to be in the same risk of
non-smoking persons in risk of cardiovascular disease. As you quit smoking, the
lungs will start to purify itself, but it will take some time. On the other
hand, it cannot be assured that the lungs may be totally restored, more or less
it would just be clean over a period of time.