For your questions, the answers would be:
Question 1: Throughout its history, the key factor contributing to Japan's economic challenges is:
- Access to natural resources.
Question 2: How did the U.S.-Japan relationship evolve or change in the years immediately following World War II?
- The U.S. played an essential role in Japan's post-World War II economic and social reconstruction, creating a lasting peaceful partnership.
If you need further clarification or more details, feel free to ask!