The only shape that fits that definition is the sphere. So, gravity is the answer to why Earth is round! If you've seen pictures of asteroids that exist in outer space, you may have noticed that some of them are irregular, rocky shapes. That's because they're not big enough to pull themselves into a sphere.
The answer is B travel across physical boundaries
It was usually performed by certain high ranking Japanese Officials and when they suffered a Major blunder in the war, or something that was considered MAJORLY unhonorable, and that's the key here, honor. Honor was HUGE in Japan, your family would consider you worthless if you didn't have honor, so doing something like losing a battle and surrendering were considered cowardly, so to maintain their honor and avoid capture they would commit Seppuku
