The correct option is A. The serosa refers to the outermost layer of loose connective tissues which is often covered by mucus and which contains blood vessels. In the gastrol intestinal tract, the serosa refers to the outermost layer of the wall of the GI tract. One major function of serosa is to reduce friction from muscle movement.
Although many states have dinosaur sites, so far the states that seem to be the most prolific producers of fossils are Colorado, Utah, Wyoming, and Montana.
