The epithelial cells of intestine are polar, what kind of connection is related to its polarity?_
                    举一反三
- What kind of food is considered to be related to animals?
 - which cell can only exit in small intestine: A: endocrine cells B: stem cells C: goblet cells D: Paneth cells E: absorptive cells
 - Pus formation largely results from the accumulation of the remains of dead and dying <br/>________. A: neutrophils B: macrophages C: epithelial cells D: sentinel dendritic cells E: red blood cells and platelets
 - What is the common part of animal cells and plant cells?
 - The cells belonging to the outermost layer of the retina are: A: Pigment epithelial cell B: Bipolar nerve cell C: Cone cell D: Ganglion cell
 
