Answer:
I believe Rome's major downfall was its fall of commerce and trade.
Explanation:
Because Rome's roads were not maintained and cared for (they had a lot of robbers and natural barriers) the trade began to decline. This must have played a major role in the decline of Rome.
<span>The correct word to fill in this blank is semantic encoding. Semantic encoding is how humans process and encode sensory input and is a psychology term. Visual imagery allows the person to gain information through viewing a situation, object or person and semantic encoding is the next step in identifying what is being viewed.</span>