Question

what caused the opium war? *
your answer

what was the positive impact of imperialism in *
china?
your answer

Explanation:

The Opium Wars were caused by British attempts to force China to accept opium trade. Britain wanted to balance trade deficits. China's restrictions on foreign trade and the opium issue led to conflict.
Regarding the positive impact of imperialism in China (though it's a complex and controversial view), some might argue that it introduced Western technology, ideas (like modern education concepts, some scientific knowledge), and infrastructure in a limited sense. But it's important to note that the overall impact of imperialism on China was extremely harmful with massive losses of sovereignty, resources, and human suffering.

Answer:

For "What caused the Opium war?": British opium trade push and trade imbalance issues.
For "What was the positive impact of imperialism in China?": Limited introduction of some Western technology/ideas/infrastructure (but with heavy caveats about overall harm).