The question is on the imagine

1 a

2 d

3 a

4 c

explanation:

i believe it is-

d.) gravity pulled particles of dust and gas together to form planets.

answer:

the reaction is type of combination reaction.

explanation:

on the product side, there are 2 molecules of bonded to fe   which means one atom of fe are combined two molecules of . so, balanced chemical equation becomes :

this reaction follows the reaction type of combination reaction. a combination reaction is defined as chemical reaction in which reactants combines together to form a single product.