Question

which results from an increase in the greenhouse effect?
continental shifts
wildfires
volcanic eruptions
global warming

Explanation:

The greenhouse effect traps heat in the Earth's atmosphere. An increase in the greenhouse effect leads to a rise in global average temperatures, which is defined as global warming. Continental shifts are due to plate tectonics, volcanic eruptions are geological events (and can sometimes affect climate but aren't a direct result of increased greenhouse effect), and wildfires are often caused by human activity or natural ignition sources, not directly by the greenhouse effect.

Answer:

global warming (the option corresponding to "global warming")