original: Because the neck is not externally visible, the head and body appear to merge together.
simplifications: Because the neck is not visible, the head and body look like they are one. The head and body appear to have no neck in the middle. The neck is not visible from the outside. The head and body look like they're together. Because the neck cannot be seen, the head and body appear to merge. Because you cannot see the neck, it looks like the head and body are together. Because the neck is not visible at its exterior, the head and body seem to merge. The neck cannot be seen from the outside, so it looks like the head and body join together without a neck. Because the neck is not visible from the outside, the head and body seem to be together. The neck is not visible from the outside. This makes the head and body appear to merge together. Since the neck is not visible externally, the head and body appear to fuse together.