Why SHOULD the NATIONAL government be in charge of stuff like the army and dealing with others countries

Sarah and joe are arrested for allegedly stealing computer equipment. which of the following is correct? the trial would only begin and end in the state court system in the state where the crime is alleged to have happened. the trial would begin in a state-level appellate court and go to the federal court of appeal if the verdict is challenged. the trial would begin in a state-level court of original jurisdiction and go to a state appellate court if either side appeals the case. the trial would begin in a u.s. district court for the circuit and go to the u.s. supreme court if either party challenges the verdict.

If there were no system of checks and balance,the process of government would eventually fall apart. do you agree with this opinion? why or why not?

How did the rise to power and reign of alexander most affect greece