Which of the following substances join together to make lipoproteins?

The formation of lipoproteins involves the combination of plasma proteins, cholesterol, and triglycerides. Lipoproteins are essential for the transportation of lipids, such as cholesterol and triglycerides, in the bloodstream, as these substances are not soluble in water. The structure of lipoproteins includes a core made up of triglycerides and cholesterol esters, surrounded by a monolayer of phospholipids along with apolipoproteins, which are the plasma proteins that play a crucial role in the stability and recognition of the lipoproteins.

This combination allows for the proper functioning of lipoproteins in lipid metabolism, including delivering cholesterol to cells and removing excess cholesterol from tissues to the liver for excretion. The other options include components that do not accurately reflect the composition of lipoproteins; for example, monosaccharides and disaccharides are carbohydrates and not involved in lipoprotein structure. Similarly, glucose and free fatty acids do not form lipoproteins as part of their primary structure. Therefore, the correct answer highlights the essential components that comprise lipoproteins and their critical roles in lipid transport within the body.