The major pillar of a country is called as the major economic activities. For example in Hawaii the major economic activity is Tourism.
What were the major economic activities of Los Angeles
Tobacco
Agriculture
tobacco
aquaculture
selling cheese is a large economic activity
aquaculture
Oil and Gas.
Major economic activities in the Persian Gulf and interior areas of the region include oil production, farming, and gas production.
wheat , corn & fishing .
they may vary