Answer is: C.) If the solid is conductive, the bonds are metallic.
1) Substances with ionic bond conduct an electric current in liquid, but not in solid state, because in liquids ions are mobile, contrary to solids where ions are fixed.
2) Substances with covalent bond not conduct an electric current in liquid and solid state, because they not have free ions or electrons.
3) Substances with metallic bond conduct an electric current in liquid and solid state, because they have mobile electrons. Most metals have strong metallic bond, because strong electrostatic attractive force between valence electrons (metals usually have low ionization energy and lose electrons easy) and positively charged metal ions.
Surface tension is defined as the tendency of elasticity of a liquid surface that makes it to achieve the possible least surface area. It depends upon the intermolecular forces present on the boundary of the surface of the compound and its contact.
n-butane 
is non-polar compound and it consist of only weak dispersion forces that are responsible for any contact with the surface.
In comparison to other given substances, n-butane has the weakest dispersion forces. Thus, n-butane has lowest surface tension.
The answer is b damaged tissue can not be repaired
The trend of atomic radius in the periodic table is increasing from right to left and from top to bottom. In reference to the table, oxygen has smaller radius compared to carbon, which is smaller than aluminum and which is also smaller than potassium. Thus, the trend from smallest to biggest is oxygen carbon, aluminum and potassium.
