What sparked irish immigration to the united states in the mid-1840s?
overcrowding, jobs on ellis island, famine, an outbreak of disease

The answer is "famine".

In the mid-1840s, the potato crops, which were the base of the Irish people diets, were distroyed by a blight, a plant disease.

The hunger forced people to emigrate, mainly to North America. They had no skills, no money, few belongings and most had no education.

i only have part a but here is the first one: - lewis and clark are born

- lewis marries sacajawea and clark is jealous  

- clark drowns lewis and then goes to jail