Answer: California and New Mexico became new states.
Explanation: K12 Quiz
In general, yes, immigration during 1830s to 1840s was vital to the industrialization of America, since it was mostly immigrants who first sought employment in the factories that were an essential element of industrialization.
The primary function of the senate was considered by the Founding Fathers as the popularly elected House of Representatives' check. Therefore, every state, regardless of the population or size, shall be equally represented. The Senate will share with the responsibility of the House of Representatives for all the lawmaking within U.S.
I would think the author is speaking about an political event in which people vote.