The fact that ice is less dense than water is related to the fact that .
Group of answer choices

the molecules are held to each other by covalent bonding

ice has a structure that is held together by hydrogen bonds

the structure of ice is much less orderly than that of water

ice has a structure in which water molecules are arranged randomly

"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."

a is the correct answer