1. How is acid rain formed?
A. Earthquakes cause tsunamis.
B. Tsunamis cause erosion to forests.
C. Volcanoes cause landslides.
D. Volcanoes emit ash and gases into the atmosphere.

2. What formed Andes mountains?
A. Oceanic-continental convergence
B. Continental-continents convergence
C. Oceanic-oceanic convergence
D. Divergent zones