The Unions strategy wa sto only give supplies and food to their soldiers at the fort, because they didn't want to start fighting in the country and start a civil war.
B: asteroids.
In the early days of the Solar System, the gravitational influence of Jupiter caused the formation of the Asteroid Belt: in this region of the Solar System, there was enough material to form planets, but then Jupiter's gravity increased the velocity of this potentially new planets, so instead of accrete they collide into each other, forming the asteroids we can observe today.
