Why were the Sung unable to survive Kublai Khan's siege? Kublai Khan used ships to block the Sung's access to rivers.
Kublai Khan used his larger army to surround the cities.
Kublai Khan used traditional Mongol fighting techniques.
O Kublai Khan used horses to attack Sung-controlled cities.

How did the united states respond when north vietnam attacked a us warship and sent troops to south vietnam in the early 1960s? a.the united states declined to assist south vietnam against the north. b.us leaders authorized south vietnam to invade north vietnam. c.the president did not sign the gulf of tonkin resolution. d.congress authorized the president to escalate the conflict.