Question

how does vitamin d affect bones?
○ vitamin d promotes the excretion of calcium from the bones.
○ vitamin d has no effect on bones.
○ vitamin d stimulates bone resorption.
○ vitamin d enhances the absorption of calcium in the gastrointestinal tract.

Explanation:

Vitamin D's key role in bone health is facilitating calcium absorption from the gut, which is essential for maintaining bone density and strength. The other options are incorrect: it does not promote calcium excretion from bones, has a critical effect on bones, and bone resorption is not its primary function here.

Answer:

Vitamin D enhances the absorption of calcium in the gastrointestinal tract.