The element that is most effective in creating the mood of the story is?

All of these elements work to create mood in this story. I found the conversations effective in bringing about the mystery and suspense. Sergeant-Major Morris spoke about the paw with ominous undertones. Mrs. White's enthusiasm, Mr. White's indecision, and Herbert White's sarcasm all heighten the suspense of using the paw. Imagery works closely with the dialogue to lure the reader into this fantastical tale.