Final answer:
High-density lipoprotein (HDL) is responsible for the reverse cholesterol transport from the periphery to the liver for excretion, which is a preventative measure against atherosclerosis.
Step-by-step explanation:
The lipoprotein theorized to transport cholesterol from the periphery, such as fat cells, to the liver for excretion in a process known as reverse cholesterol transport, is high-density lipoprotein (HDL). HDL is composed of approximately 33% proteins and 67% lipids, mainly phospholipids, and cholesterol. This lipoprotein takes up cholesterol from tissues and carries it back to the liver, where it can be reused or excreted. This function of HDL in reverse cholesterol transport is a protective mechanism against atherosclerosis, earning it the nickname of "good cholesterol." HDL is considered beneficial because it helps maintain a healthy balance of cholesterol in the body and prevents the buildup of plaques in arterial walls, which can lead to cardiovascular diseases.