Final answer:
The federal government took on various responsibilities once Texas joined the Union, such as managing debts, addressing the expansion of slavery, and sharing powers with the state to collect taxes and enforce laws. The admittance of Texas as a slave state in 1845 intensified national tensions over slavery as America pursued its 'Manifest Destiny.'
Step-by-step explanation:
Once Texas became a state, the federal government was responsible for various duties, including the assumption of Texas's debts from its days as the Lone Star Republic, and matters related to its status as a slave state. The federal government had to navigate sensitive issues such as the expansion of slavery, particularly as Texas's annexation could potentially upset the balance of power between free and slave states.
This was a contentious issue as Texas was admitted to the Union in 1845, during a time when the concept of "Manifest Destiny" encouraged westward expansion and heightened sectional tensions over slavery.
The federal government also shared concurrent powers with state governments. These included the ability to collect taxes, establish courts, make and enforce laws, build roads, provide for education, and borrow and spend money. The introduction of Texas as a state meant that its citizens were now subject to both federal and state laws, which could include legislation around the slave trade, as well as more general civil responsibilities.