Blank is a type of complex carbohydrate that is not digested by the human body or broken down into sugar as other carbohydrates are.

A. Vitamins
B. Water
C. Fat
D. Fiber

D. Fiber

D. Fiber

The correct answer is D. Fiber. Fiber is a type of complex carbohydrate that cannot be digested by the human body. It passes through the digestive system mostly intact because humans lack the necessary enzymes to break it down. Instead of being broken down into sugar like other carbohydrates, fiber helps add bulk to the stool, regulate bowel movements, and can have various other beneficial effects on health.

To find the answer to this question, one can understand the concept of different types of carbohydrates and how they are processed in the human body. By knowing that fiber is a type of complex carbohydrate that is not digested or broken down into sugar, it becomes clear that fiber is the correct option. Additionally, one can refer to reliable sources such as nutrition textbooks, health websites, or consult with a nutritionist or dietitian for accurate information on carbohydrates and their digestion.