Why are lipids unable to freely travel in the watery plasma?

Lipids, including cholesterol, triglycerides, and fat-soluble vitamins, are hydrophobic — they repel water and therefore cannot dissolve or travel freely in the watery, aqueous plasma. Because plasma is approximately 91% water, hydrophobic molecules would clump together rather than dispersing evenly if they were transported in their free form. To overcome this, the body packages lipids into lipoprotein carriers (such as LDL, HDL, VLDL, and chylomicrons), which have hydrophilic outer shells that allow them to remain suspended in plasma. The option stating lipids are 'not produced in the liver' is incorrect because many lipids are indeed synthesized in the liver; production site is unrelated to plasma solubility. 'Too large' is incorrect because lipid molecules are actually quite small; the size barrier does not prevent plasma travel. 'Hydrophilic' is the opposite of the correct property — hydrophilic substances dissolve readily in water. Understanding hydrophobicity explains why lipoprotein transport is necessary and why elevated lipoproteins are measured in cardiovascular risk assessments.