Location b is most likely going to form a mountain over time if the tectonic plates are underneath or on top of each other
I would go with the war with Somalia, because first all the other answer seem correct and the war with Somalia was a major victory for Ethiopia, they gained from it. So the answer is "war with Somalia"
They give more/additional information about a certain topic of research.
They help learns to know what they may expect to see on the field
Make the united kingdoms flag that should work