The Liver The Liver Is One of the Largest and Most Vital

The Liver
The liver is one of the largest and most vital organs in the body. It is located on the right side of the body and is protected by the rib cage. The liver performs many important jobs, including breaking down nutrients, removing toxins, and destroying damaged blood cells.
The liver's main function is to filter blood. Blood travels to the liver from the digestive tract. The liver processes this blood, removing toxins and metabolizing nutrients. The liver also secretes bile during this process. Bile is stored in the gallbladder and released into the large intestine. Bile aids in the digestion of fats. The liver also makes proteins necessary for blood clotting, removes worn-out blood cells, helps to regulate blood sugar levels, and stores vitamins A, D, E, K, and B12.
There are several diseases that can affect the liver. Because the liver performs so many important functions in the body, liver problems can be life-threatening. Hepatitis is a disease characterized by inflammation of the liver. Left untreated, certain types of hepatitis can be fatal. Cirrhosis is another dangerous liver condition. Cirrhosis develops when healthy liver tissue is replaced by scar tissue. This is most often caused by long-term alcohol abuse. Cirrhosis can cause swelling, internal bleeding, and eventually, liver failure. The only cure for cirrhosis is a full liver transplant.
What is the meaning of the word 'regulate' in the last sentence in paragraph 2?

A) To study the effects
B) To increase speed
C) To replace with a better option
D) To manage something