Which of the following is NOT a primary function of the digestive system?

• A. Mechanical and chemical breakdown of food into smaller molecules
• B. Elimination of indigestible material and waste as feces
• C. Absorption of nutrients, water, and electrolytes into the body
• D. Production of red blood cells in the bone marrow

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the primary functions of the digestive system. The digestive system is mainly responsible for breaking down food, absorbing nutrients, and eliminating waste.
2. Step 2: Identify the functions listed in the problem: mechanical and chemical breakdown of food, elimination of waste as feces, absorption of nutrients, water, and electrolytes, and production of red blood cells in the bone marrow.
3. Step 3: Recognize that mechanical and chemical breakdown of food involves processes like chewing and enzymatic digestion, which are core digestive functions.
4. Step 4: Note that absorption of nutrients, water, and electrolytes into the body occurs primarily in the small intestine, another key digestive role.
5. Step 5: Understand that production of red blood cells in the bone marrow is a function of the skeletal and hematopoietic systems, not the digestive system, making it the correct answer as the function NOT related to digestion.