what was the purpose for the naval expeditions of the ming dynasty?

they wanted to expand trade.

they were curious about other nearby lands.

they were looking for new lands to conquer.

they wanted to be sure the mongols were gone.

The picture below shows president richard nixon and the first lady standing before the great wall of china in 1972. they are smiling - as are the chinese with them. when this picture was shown on american television, americans were aware that it was a historic moment. what are two reasons why this moment was important for both china and the united states?