1, Mass Wasting, 2, Heavy Rain, I believe.
The correct option is B.
The field of science is very dynamic and it thrives on discovery of new evidences. When new evidence are found for a particular phenomenon, the existing phenomenon has to be adjusted to fit the new discovery. Air pollution was once named to be responsible for global cooling because enough evidence was not available then to prove otherwise but now overwhelming evidences show that pollution is responsible for global warming.<span />
