Final answer:
The Irish potato famine was caused by the susceptibility of the single variety of potato grown in Ireland to a potato blight, which was worsened by asexual crop production.
Step-by-step explanation:
The Irish potato famine was caused by the susceptibility of the single variety of potato grown in Ireland to a potato blight, leading to the destruction of the entire crop. The loss of the potato crop resulted in mass famine, the death of over one million people, and the emigration of nearly two million people. Asexual crop production, which involves planting genetically identical individuals, contributed to the severity of the famine because the lack of crop diversity made the entire crop vulnerable to the blight.