Machinery, electrical equipment and parts.
grain
grain
cotton
It is the most profitable mineral exported by Mexico, generating revenues of US$5.83 billion or 2% of total exports.
During 2013, Mexico exported US$45.9 billion, worth of crude oil, representing 13.16% of total exports.
A better question is where is corn not exported. The largest importer of US corn is Japan at ~23% ($ value) followed by Mexico at ~18%.
Because not all cars are assembled in Mexico. For instance, Mexico produces windshields which are then exported into the US and later assembled as finished cars in the United States.
US exports into Mexico accounted for some USD$112 billion during the year 2000.
Tobacco, from Kentucky.
deodorant
Oil would qualify as Mexico's most important resource, providing US$35 billion, or 12% of total exports each year. Its most important product would be fully-assembled motor vehicles, providing US$24 billion, or 7.9% of total exports.
Oil is exported from southeast Asia, Africa, the North Sea, Venezuela, Mexico, Canada, and the US.