ammonium compounds are less effective against gram-negative bacteria and more effective against gram-positive bacteria.

Quartenary.

Explanation:

Quaternary ammonium compounds (QACs) are cationic salts of organically substituted ammonium compounds and have a broad range of activity against microorganisms, i.e more effective against Gram-positive bacterium at lower concentrations than Gram-negative bacteria.

It was also reported previously that monoalkyl QACs bind by ionic and hydrophobic interactions to microbial membrane surfaces, with the cationic head group facing outwards and the hydrophobic tails inserted into the lipid bilayer, causing the rearrangement of the membrane and the subsequent leakage of intracellular constituents.

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.

it’s previous models   because when i picked that son of a gun’s answer it was wrong look for previous models because they might make it a different letter