Which organ is crucial for the absorption of water and electrolytes?

The large intestine plays a critical role in the absorption of water and electrolytes. As food residue passes through the large intestine, the body extracts remaining fluids and essential ions, such as sodium and potassium, from the waste material. This process helps to maintain the body’s fluid and electrolyte balance, which is essential for various physiological functions, including nerve conduction and muscle contraction.

Moreover, most of the water and electrolytes are absorbed in the large intestine, which can adapt to the body's hydration needs. If the body is dehydrated, the large intestine can increase its absorption capabilities, leading to more concentrated waste.

In contrast, the small intestine primarily focuses on the digestion and absorption of nutrients from food rather than water and electrolytes, although it does absorb some fluid. The kidneys play a significant role in regulating electrolyte balance and waste elimination but do so after the absorption processes have occurred in the intestines. The liver is involved in many metabolic processes but is not directly responsible for the absorption of water and electrolytes from the digestive tract.