The fear that if vietnam would fall to communism, then neighboring countries would follow suit

Which of the following descriptions is an example of the curtual diffusion

Plz which of the following statements about spanish plantations is not accurate? a. spanish plantations grew sugarcane for export to spain b. the spanish had little concerned for the lives of the indians who worked on the plantations. c. spanish plantations grew wide variety of crops and center produce to many different european countries. d. to replace the native americans our dying off the spanish imported african slaves.

The information box says that the han added 4,000 miles of wall.refer to the mileage scale.how can this be true?