The Boxer Rebellion was a response to the growing resentment among the Chinese towards foreign intervention and control in their country. This resentment was fueled by the presence of foreign settlements and spheres of influence, as well as the influence of secret societies pledging to rid China of foreigners. rephrase like a 8th grader

The Boxer Rebellion happened because the Chinese were really mad about foreign countries getting involved in their country. They didn't like that these other countries had areas where they controlled things and they also didn't like the secret groups who wanted to kick out foreigners.