Final answer:
The Irish Potato Famine had multiple effects on the United States, including a decline in immigration and an increase in the Irish immigrant population.
Step-by-step explanation:
The Irish Potato Famine had several effects on the United States. One of the effects was a decline in immigration, which is option B. The famine in Ireland led to a significant increase in Irish immigrants to the United States, as people sought to escape the starvation and hardship in their home country. Another effect was an increase in the Irish immigrant population in the United States, which is option D.
The famine forced many Irish people to leave their homeland and seek refuge in the United States. As a result, the Irish immigrant population in the U.S. grew significantly during this time period. This wave of Irish immigration had a lasting impact on the United States, shaping its culture, politics, and society.
In conclusion, options B and D are the correct answers. The Irish Potato Famine led to a decline in immigration and an increase in the Irish immigrant population in the United States.