❓ คำถาม According to the passage, why are supporting services often neglected in discussions of ecosystem services?
- A. A. They are less important than provisioning services.
- B. B. They are difficult to quantify because they lack direct, immediate benefits.
- C. C. They are only relevant in terrestrial ecosystems, not aquatic ones.
- D. D. They have been fully integrated into economic valuation models.