3- Epithelial cells: A. Are polarized cells. B. Are mobile. C. Contain cytokeratin intermediate filaments. D. Contain epithelial membrane antigens (EMA) in their cytoplasm. E. Are contiguous cells. F. Derived only from the mesoderm. G. Contain specific intermediate filaments. H. Are isolated cells. I. Involvement of RBC progenitors, or of the stem cell

A. True. Epithelial cells are polarized, meaning they have a distinct top and bottom. This allows them to perform specific functions such as absorption and secretion.

B. False. Epithelial cells are not typically mobile. They are tightly bound to each other in sheets or layers to form a barrier.

C. True. Epithelial cells contain cytokeratin intermediate filaments, which are part of the cytoskeleton and provide structural support.

D. True. Epithelial cells contain epithelial membrane antigens (EMA) in their cytoplasm. These antigens can be used as markers in cancer diagnosis.

E. True. Epithelial cells are contiguous, meaning they form a continuous layer or sheet of cells.

F. False. Epithelial cells are not only derived from the mesoderm. They can also originate from the ectoderm and endoderm.

G. True. Epithelial cells contain specific intermediate filaments, which are part of the cytoskeleton and provide structural support.

H. False. Epithelial cells are not isolated. They are tightly bound to each other in sheets or layers to form a barrier.

I. False. The involvement of RBC progenitors, or of the stem cell, is not a characteristic of epithelial cells. This is more relevant to hematopoietic cells.