Final answer:
The primary function of the large intestine is absorption, particularly reabsorbing water and salts and forming and eliminating feces. It contains multiple regions including the cecum, colon, and rectum, all playing a role in waste processing and defecation.
Step-by-step explanation:
The primary function of the large intestine is absorption. Specifically, the large intestine is responsible for absorbing water and salts from the remaining digested material, or chyme. This reabsorption is crucial for recycling these substances within the body. The large intestine also plays a key role in forming and eliminating solid feces through the anus. Additionally, it contains bacterial flora which help digest certain compounds, produce vitamins, stimulate the immune system, and break down toxins. The structure of the large intestine includes the cecum, the colon (which has ascending, transverse, descending, and sigmoid sections), and the rectum. While the colon stores waste material, the rectum activates the defecation reflex.