<span>John D. Rockefeller did everything by his own. Vertical integrations means that he employed his own workers, then he constructed barrels to store oil and rent wagons and horses to transport that barrels. So it's called vertical integration. </span>
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The Open Door policy—first initiated in 1899, with a follow-up missive in 1900—was significant in its attempt by the United States to establish an international protocol of equal privileges for all countries trading with China and to support China's territorial and administrative integrity.
Explanation:
