5. When considering the nature of genetic regulation in eukaryotes, one often comes across theterm "housekeeping genes". We could expect that such housekeeping genes would
(A) provide mRNAs which are not protected at their 5' and/or 3' ends
(B) be active only in heart and liver cells because they are the most vital cells in an organism
(C) code for proteins which are essential for all cells of an organism
(D) provide hnRNAs which do not undergo intron removal
(E) code for proteins which are found only in certain cell types