the answer is core region
Explanation:
The electrons on the outermost energy level of the atom are called <u>valence electrons</u>. The valence electrons are involved in bonding one atom to another. The attraction of each atom's nucleus for the valence electrons of the other atom pulls the atoms together.
In my opinion the louisiana purchase because it expanded US territory by 828,000 square miles and started the westward expansion of the US
There are multiple factors such as disease and invaders from outside and even conflicts within Rome but maybe the invaders were the problem because they ended up being the reason why Rome fell.
