For the first question we say that is an absolute phrase because it combinesa noun and a participle with any acompanying modifier or object. For the second question we can see that the mood of this oart of the passage os dreary as it describes fog and many creepy and sad situations related to it. And for the 3rd question we can say it is a slow pace, even there are many sentences, he takes the time to describe or give more information to the reader for many of the sentences of this paragraph, something that surely cannot be told in a fast pace
The correct verb form would be a. came. Hope this helps!
They explain through storytelling how things came to be or how the world came into existence.
