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.
The lower respiratory tract is sometimes referred to as the tracheobronchial tree, this describes the branching structure of airways supplying air to the lungs, this includes the trachea, bronchi and bronchioles.
Explanation:
this is whorl fingerprint
That’s a dependable variable because it’s relying on something else.
