36. The most significant international undertaking to prevent worsening of global warming is the a. Montreal Protocol b. Rio Declaration c. Agenda 21 d. Kyoto Protocol e. None of the above 37. Common ownership of resources such as land can be efficient as long as a. people are honest b. government regulates resource use c. rules for resource use are clear in assigning rights and responsibilities d. penalties for misuse are severe e. all the above are required 38. Natural resources should be left in the ground a. if their discounted future value exceeds their current value b. so future generations will be able to use them c. until companies agree to restore land after mining d. because we may run out e. economists have no good way to analyze this