The direct cause of u. s. involvement in world war ii wasa)germany's invasion of poland.
b. the japanese attack on pearl harbor.
c. sinking of the lusitania by germany.
d. italian mistreatment of foreign nationals by the us.

The correct answer is B) The Japanese attack on Pearl Harbor.

The US was attacked by the Japanese Empire on December 7, 1941. On this day, Japan attacked the US military base in Hawaii, killing thousands of soldiers and civilians. The next day, president Franklin D. Roosevelt went before Congress to ask them to officially declare war on Japan. Congress obliged and as of December 8, 1941 the US was at war against Japan.

zheng he was a chinese explorer who lead seven great voyages on behalf of the chinese emperor. his seven total voyages were diplomatic, military, and trading ventures, and lasted from 1405 – 1433. however, most historians agree their main purpose was to promote the glory of ming dynasty china.

explanation:

cultural/diplomatic relations. most medieval japanese   culture has chinese origins. writing, architecture etc.