Which branch of government has the power to declare acts (laws) of congress unconstitutional?

Need on these last 2 questions on my social studies homework 5 and 6 then i’m done with the homework

According to the sixth amendment, what can the woman do to support her court case? 1/ she can hire a different lawyer. 2/she can request that the trial be moved to a different state. 3/ she can require the witnesses to testify. 4/ she can refuse to testify.

It is 1825 and you have recently moved from the family farm to new york city. write a letter to a friend describing what your new life is like.