(a) Compare the specifific-factors model and the Heckscher-Ohlin model. List three differences between these two models, and explain how the differences lead to different model predictions.

(b) What is the Leontief's Paradox? Explain what Wassily Leontief's finding is and why it is paradoxical. List at least three possible explanations for Leontief's Paradox.

(c) Explain why the Mariel Boatlift provides a good opportunities for economists to study the impact of immigration on American labor market.