Answer:
A. Fewer Nesting Sites.
Explanation:
if birds are spreading a disease to the trees that kills them off then that would lead to birds having less places for shelter, since that's the main thing they use trees for, unless were talking specifically about fruit and nut producing trees, then it would not only be lost of nesting sites, but it would also eventually be a loss of a food source as well.
Tsunami, I think, maybe a flood
Carbo dioxide, water and sun's energy comes fron the outside.... energy and Oxygen molecule are produced
