Fats enter the blood as ______ and leave the liver as _______.

Fats are transported in the body in a specific manner that facilitates their movement through the bloodstream and into various tissues. Initially, fats in the intestines are broken down and re-esterified into triglycerides, which then aggregate into particles known as chylomicrons. These chylomicrons enter the bloodstream after intestinal absorption, where they transport dietary lipids from the intestines to other areas of the body.

Once fats are processed by the liver, they are packaged into various types of lipoproteins for distribution. The liver converts some of the absorbed fats into different forms, including very low-density lipoproteins (VLDL), which are a type of lipoprotein that carries fats away from the liver to be used by other tissues. Thus, fats leave the liver as lipoproteins.

This understanding underlines the correct answer, which states that fats enter the blood as chylomicrons and leave the liver as lipoproteins. The terminology used here reflects the process of fat transport and metabolism: dietary fats initially packaged as chylomicrons and then repackaged in the liver as lipoproteins for systemic distribution.