Question

what are some possible causes of tsunami? (pick the best answer)
earthquakes
all of these could cause tsunamis
meteorites
landslides
nuclear detonations

question 2
what natural type of wall often absorbs tsunami wave energy; such as the one located just north and northeast of australia?
coral reefs
sand dunes
seawalls
barrier islands

Explanation:

For the first question, tsunamis can be caused by earthquakes (due to sudden movement of the ocean floor), meteorites (impact can displace water), landslides (mass movement into water), and nuclear detonations (artificial energy release). So all these can cause tsunamis. For the second question, coral reefs (like the Great Barrier Reef near Australia) are natural structures that can absorb wave energy.

Answer:

1. all of these could cause tsunamis
2. coral reefs