Answer: The Great Famine or The Irish Potato Famine was caused by a failure of the potato crop, which many people relied on for most of their nutrition.
Explanation: A disease called late blight destroyed the leaves and edible roots of the potato plants in successive years from 1845 to 1849. The blight was infectious and contagious, so many people died. Some people had no choice but to eat the infectious potato crop, or else they would die of starvation.