What is one of the main functions of the liver?

The liver plays a critical role in regulating chemical levels in the blood, making it essential to overall body function. One of its primary functions is to process nutrients absorbed from the digestive tract and to maintain homeostasis, which involves keeping the levels of various substances, such as glucose, hormones, fats, and proteins, within a healthy range.

For instance, when blood sugar levels rise after a meal, the liver converts excess glucose into glycogen for storage. Conversely, when blood sugar levels drop, the liver can convert glycogen back into glucose and release it into the bloodstream. This regulatory capability is crucial for maintaining metabolic balance and ensuring that the body has a consistent supply of energy.

The other options relate to functions that either do not occur in the liver or are predominantly associated with other organs. For instance, insulin production is primarily associated with the pancreas. While the liver does have roles in fat metabolism, its main function is not solely storing fat, and it does not filter oxygen; that is a function of the lungs. Therefore, the liver's ability to regulate chemical levels effectively in the bloodstream is a key part of its physiology and vital to maintaining health.