Answer:
Magnesium
Explanation:
Magnesium is above iron in the reactivity series, which means that Mg can take oxygen from iron as it is a more reactive metal.
Mold fossils (a fossilized impression made in the substrate - a negative image of the organism)cast fossils (formed when a mold is filled in)trace fossils = ichnofossils (fossilized nests, gastroliths, burrows, footprints, etc.)
The question is asking to state the substance that is acting as the Bronsted Lowry base in the forward reaction, base on my research, I would say that the substance acting to said formulas is the NH3. I hope you are satisfied with my answer and feel free to ask for more if you have question and further clarification
