Which of the following statements about Gauss's law are correct? (There may be more than one correct choice.)
1. The electric flux passing during a Gaussian surface depends only on the amount of charge inside that surface, not on its size or shape.
2. If a Gaussian surface is completely inside an electrostatic conductor, the electric field should always be zero at all points on that surface.
3. If there is no charge inside of a Gaussian surface, the electric field should be zero at points of that surface.
4. Gauss's law is valid only for symmetric charge distributions, such as spheres and cylinders.
5. Only charge enclosed within a Gaussian surface can produce an electric field at points on that surface.