Rome’s location gave it a natural advantage because

I big advantage that its location gave it was that it was situated on the Italian peninsula , giving it very large access to trade with anyone in the Mediterranean sea.

Explanation:

the answer to fill in the blank in this question would be the word resource, it is defined as the money, material or people (since human resource is a very valuable good) that a company or a person has at disposition (meaning they can use the resource as they see fit), to be able to complete a task or achieve a goal.