MY TEST IS TIMED NEED HELP Why do nations establish trade barriers?

A. Trade barriers promote equality among nations, ensuring that everyone produces similar
products.
B. Trade barriers eliminate sanctions and embargoes between nations.
C. Trade barriers limit the movement of people from one nation to another.
D. Trade barriers protect a nation's interests by encouraging the production of homeland goods.

true. earthquakes are felt whenever there is a slip around a fault in the rocks below the earth. this reorientation of faults create sesmic waves and is known as earthquake, the severity of which is measured in richter scale. these are more prominent in hilly regions as the rocks usually form faults to balance the pressures on it.

question

which are human systems?

the amazon rain forest

the appalachian trail

the george washington bridge

the himalayas

the hoover dam

the north american free trade agreement