Please help me to answer it

1. Explain what are WTO's and Canada's requirement for granting of preferential tariff treatment on goods imported into Canada.

2. Explain to the importance of "transshipment" and what the requirements for the goods to maintain preferential tariff in the country of transshipment. If the country of transshipment is not eligible for the preferential tariff the same as the exporting country. The final destination of the goods is Canada.