What is a tsunami?

Question

a. It is a giant wave caused by an underwater earthquake.
b. it is a giant wave, but no one knows what causes it
c. it is a giant wave causes by a volcano

Answer 1

a. It is a giant wave caused by an underwater earthquake.

Tsunamis are typically the result of underwater tectonic activity, such as earthquakes, but they can also be caused by volcanic eruptions, landslides, or meteorite impacts. However, the most common cause is underwater earthquakes.