Which reason is the best for choosing the ruler to measure the dimensions of the wooden block?

a meter stick is only marked in customary units and is therefore inappropriate.

a tape measure is simply not accurate.

a ruler is a good length for measuring the length of fairly small objects.

only rulers are marked in centimeters, so no other tool will work.

nacl is added to the aqueous of what? ? in order to get a proper answer you have to specify the exact composition of the aqueous solution.

"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."