1. No
2. USA in Wheat and Lumber both
3. Opportunity cost is less than 1
4. Canada.
Step-by-step explanation:
1. To produce 16000 tonnes of Lumber and 50000 tonnes of wheat US would require 160000 labor hours which is not available.
2. USA produces more lumber and wheat in less worker hours and hence in less rates so clearly has an advantage.
3. Opportunity cost is the cost incurred when one alternative is chosen over another. As producing wheat takes less time than lumber, it is preferable to produce is and thus no opportunity cost is incurred that would be more than the produce.
4. Canada. Because US produces wheat more cheap and thus it will be easier to export than to make own wheat which is expensive.