Answer:
The correct answer is option D.
Explanation:
Step 1: 
Step 2: 
Overall reaction can be determined by adding all the reactions of mechanism:

Reactants in an overall reaction = 
Products in an overall reaction = 
According to question , the role of oxygen gas is product.
I think it’s 5000 because it says that their is over 4,124 valid species of minerals.
Ionic is the answer. This is because lithium has a positive charge, while chlorine has a negative charge, meaning the compound doesn’t necessarily have an overall charge.
The form of heat transfer taking place in the crust of the Earth would be Convection.
Answer:
Obtención. El carbono se encuentra - frecuentemente muy puro - en la naturaleza, en estado elemental, en las formas alotrópicas diamante y grafito. El material natural más rico en carbono es el carbón (del cual existen algunas variedades). Grafito: Se encuentra en algunos yacimientos naturales muy puro.