❓ 質問 According to the passage, what is a primary reason ecosystem services are often undervalued in traditional economic systems?
- A. A) They are difficult to quantify because they are intangible.
- B. B) They are considered public goods, leading to market failures.
- C. C) They have only recently been recognized by policymakers.
- D. D) They are mainly provided in developing countries with weak institutions.
