Final answer:
Sally's inability to absorb certain nutrients in her small intestine suggests a dysfunction in the epithelial tissue lined with microvilli, critical for nutrient absorption.
Step-by-step explanation:
The tissue type that might be dysfunctional in Sally's small intestine is epithelial tissue. This tissue is specialized for absorption and is lined with microvilli, which are fingerlike extensions that increase the surface area for efficient nutrient absorption. When these microvilli are damaged, as occurs in individuals with celiac disease who cannot tolerate gluten, nutrient absorption is compromised. In Sally's case, the inability to absorb nutrients suggests a similar dysfunction that affects the villi or microvilli in the small intestine.