IB Physics Relativity of E and B fields

A tutorial sheet of questions on E and B fields is given below.

1. A uniform magnetic field is along the z-axis. A reference frame moves relative to the magnetic field with its velocity vector parallel to the x-axis. Describe the fields according to an observer in the moving reference frame.
2. A uniform electric field is along the z-axis. A reference frame moves relative to the electric field with its velocity vector parallel to the x-axis. Describe the fields according to an observer in the moving reference frame.
3. Without special relativity there is no magnetism. Magnetic effects are a consequence of Einstein's special theory of relativity. True or false?
4. Does Newton's third law apply in special relativity?