Lol, take it from a dude whose main username is White Shadow, and loves riddles
The answer is Shadow
It only appears where there is light, but if light has direct contact with it, such as a flashlight beam, it'll fade.
There were actually several building techniques that were introduced by the Romans, but perhaps the most important was the bridge building technique that allowed bridges to be built without supports.
Answer:
I am pretty sure it's 2 and why does my answer have to be so long it won't let me submit so just ignore everything after the 2
