Final answer:
The primary cause of the Sepoy Rebellion was the use of animal fat on rifle cartridges, which deeply offended Hindu and Muslim soldiers in the British Indian Army, along with other grievances such as low pay and harsh treatment.
Step-by-step explanation:
The Sepoy Rebellion, also known as the Indian Rebellion of 1857, was caused by multiple factors, but the primary cause was the use of animal fat on rifle cartridges. The cartridges were greased with animal fat, specifically beef and pork fat, which deeply offended Hindu and Muslim soldiers in the British Indian Army. This religious insensitivity, along with other grievances such as low pay, harsh treatment, and disregard for Indian customs, led to widespread resentment and eventually fueled the rebellion.
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