Why don't trees spontaneously catch on fire and burn all the time? Why don't fires stop immediately as soon as they start? Develop a model for what has to happen for a large fire to occur.

Both of these phenomena is due to the ignition temperature.

Explanation:

Since a twig's surface area is not much larger than its volume, it ignites quickly. By comparison, a tree's surface area is much smaller than its volume, so it needs more time to heat up before it ignites.

the solar system used to have much dust particles option no d

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.