Professor Webb has discovered a new planetary system around a Sun-like star! Which of the following observations of Professor Webb's planetary system can be explained with the Nebular Theory? Check ALL that apply:
1. There is a Saturn-sized planet located 0.5 AU away from the Sun-like star.
2. There is a Mercury-sized planet located inside the planetary system's frost line.
3. The Jovian planets have moons orbiting in prograde orbits.
4. All the planets in the system orbit in the same direction.
5. All the planets orbit in the same plane.