"For the increase of the shipping and the encouragement of the navigation of this nation, which under the good providence and protection of God is so great a means of the welfare and safety of this Commonwealth: be it enacted by this present Parliament, and the authority thereof, that from and after the first day of December, one thousand six hundred fifty and one, and from thence forwards, no goods or commodities whatsoever of the growth, production or manufacture of Asia, Africa or America, or of any part thereof; or of any islands belonging to them, ... shall be imported or brought into this Commonwealth of England, ... in any other ship or ships, vessel or vessels whatsoever, but only in such as do truly and without fraud belong only to the people of this Commonwealth, ... under the penalty of the forfeiture and loss of all the goods that shall be imported contrary to this act."From the Navigation Act, 1651

Which aspects of the Navigation Act most clearly support the British idea of mercantilism?