What is the role of the liver in metabolism?

The liver plays a crucial role in metabolism by processing carbohydrates, fats, and proteins, making option B the correct choice. In the context of carbohydrates, the liver helps to regulate blood glucose levels by converting excess glucose into glycogen for storage and releasing it back into the bloodstream when needed. For fats, the liver is involved in the metabolism of lipids, converting them into energy or storing them for future use. It also plays a vital role in protein metabolism by synthesizing essential proteins, converting ammonia to urea for excretion, and facilitating the breakdown of amino acids.

While the liver does break down toxins, store vitamins and minerals, and contribute to pancreatic functions by responding to insulin, its primary metabolic activities are centered around processing macronutrients, which highlights the importance of option B in understanding the liver's functions in the body.