The answer is ... 16 I think
Canada has a lot of natural resources -this is one of the reasons why it's in such a strong position. Another reason why it's so strong is that it has ports on both the Atlantic Coast and the Pacific coast - so it can trade with both Europe, Africa and Asia.
B, p waves go through all of the layers of the earth
Since break of bulk is where cargo ships unload, local areas that have ports would have resources shipped in. the economic advantages to local populations is that they have demand from other areas wanting those resources so the port cities get money for giving their resources to non-port cities.