The majority of tsunami are caused by underwater the majority of tsunami are caused by underwater fault movement meteorite impacts turbidity currents avalanches volcanic eruptions

The answer would be:

Fault Movement

Most tsunamis are caused by fault movement and to be more specific, at subduction zones. Subduction zones are areas where oceanic plates slide under continental plates. This causes friction between the two plates and the energy that is generated there is enormous. This release of energy causes earthquakes which is a primary cause of tsunamis.

b.

developed countries have tended to improve the environment, while developing countries have tended to damage it.