About the level represented by the characteristics of "high-low-high-low-high" echo in the wall of the stomach from the inside to the outside, what is wrong is ( ). A: mucosal surface and interface B: mucous muscularis C: submucosa D: the muscularis propria E: Interface and serosal layer

Which is correct about the villus of small intestine() A: It can swing B: It is composed of simple columnar epithelium C: It is formed by mucosa and submucosa protruding into enteric cavity D: It is related with transportation of water and electrolyte E: It is formed by simple columnar epithelium and lamina propria<br/>protruding into enteric cavity