What is the role of neutrons in the nucleus of an atom?

Great amounts of electromagnetic energy from our sun and other bodies in space travel through space. which is a logical conclusion about these electromagnetic waves? their energy must be very their frequency must be very low these waves can travel without a medium they only travel through a vacuum of space

Can someone me with 3 and 4 plz. this is for masteries test.

Which states of matter have particles that move independently of one another with very little attraction?