I think that a) is chemical, and b) would be chemical
Answer:economia factores unas veces es como propiedad de algo de hacen por el dinero o sus benificios
Explanation: espero que ayude ✨✌
Asteroids are made up of metals, oxygen and silicon. Comets are made up of ice, dust and rocky material.
Because Earth Sciences covers a lot of ground (pun intended) and nobody has the time or ability to do everything well and thouroughly. The field is very highly specialized in its subdivisions.
