Answer: The substance that is not soluble in the water and can accumulate it on the inner walls of arteries is the cholesterol.
Explanation: The cholesterol is not soluble in the water because it's chemical structure belongs to the lipids. The lipids are natural oils, so in that way, the water can't disolve them due to different polarities on their molecular structures. Also, the lipids flow resistance is higher than the blood flow resistance. For this reason, the lipids viscosity and the quantity of it that he body can contain, the lipids start to adherence to the arteries inner walls creating an obstruction that will blocking the blood circulating generating future healthy problems.