Examination of the amino acid composition of a newly isolated protein indicates the presence of 10 lysines, 5 arginines, and 3 methionines. When the protein is treated with cyanogen bromide, four peptides are obtained. When it is treated with trypsin, 15 peptides are obtained. What do these results suggest regarding the sequence of the protein? A. The protein has a lysine or methionine at its C-terminal end. B. The protein is cyclic in nature with no free N or C-terminal ends. C. The protein has a lysine or arginine at its C-terminal end. D. The protein does not have lysine, arginine, or methionine at its C-terminal end.

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."