Japan wanted to control to expand its overseas empire.

they wanted to control Korea to expand its overseas empire

Explanation:

Japan's prosperity depended heavily on trade and the depression forced other countries to cut back on imports. Many countries raised tariffs on imports to protect their own industries.

Also , In 1910, Korea was annexed by the Empire of Japan after years of war, intimidation and political machinations; the country would be considered a part of Japan until 1945. In order to establish control over its new protectorate, the Empire of Japan waged an all-out war on Korean culture.

this null effect is caused by a weak manipulation and ineffective internal validity. in a scientific study, as the one dr. morimoto is trying to perfom, internal validity refers to the confidence placed in the cause-effect relationship and to how well an experiment is done and able to eliminate confounding variables.