Final answer:
a) Absorption of nutrients increases
A small intestine shaped like the stomach would decrease the surface area for nutrient absorption, hindering the efficiency of digestion due to the lack of villi and microvilli which are essential for maximizing absorptive capacity.
Step-by-step explanation:
The question posed addresses the importance of the shape and structure of the small intestine in human digestion and nutrient absorption. If the small intestine were shaped like the stomach, a major disadvantage would be that the surface area for absorption decreases. The small intestine contains structures known as villi and microvilli that significantly increase the surface area, which is crucial for efficient nutrient absorption. Villi are finger-like projections, and microvilli are even smaller projections on the epithelial cells, both enhancing the surface area available for absorption.
When villi are damaged, it impairs nutrient absorption, illustrating their importance. The large surface area provided by these structures ensures that nutrients from digested food are absorbed efficiently into the bloodstream, to be distributed throughout the body.