What do comets and asteroids have in common​

Theyre both celestial bodies orbiting our Sun, and they both can have unusual orbits, sometimes straying close to Earth or the other planets. ... While asteroids consist of metals and rocky material, comets are made up of ice, dust, rocky materials and organic compounds.

B) Steel production

I finished the test with an almost perfect score, but I'm 100% sure because it needed to be mass produced to build railroads.