PPC Shifts from Resource and Technology Improvements

Steps:

• Recall that an outward PPC shift requires increased productive capacity, such as more resources, better technology, or improved labor skills.
• Evaluate options for factors that enhance overall production possibilities for sweet potatoes and onions.
• Identify D as involving human capital (training) and technological advances in onion production, boosting efficiency.
• Confirm other options involve demand-side changes or movements along the existing PPC, not shifts.

Why D is correct:

• Training and technology improve productivity and efficiency, expanding the economy's resource base per the PPC definition of attainable output combinations.

Why the others are wrong:

• A: Fuller resource use moves along PPC1; price changes affect demand, not supply capacity.
• B: Onion price reduction shifts demand; "sweet potato population" likely means consumer growth, not productive resources.
• C: Onion price increase and sweet potato preference alter allocation points on PPC1, not the curve itself.

Final answer: D