Answer the following question given this paragraph: 

Particles with opposite electric charges attract each other. This explains why negative electrons orbit the positive nucleus. Particles with the same electric charge repel each other. This means that the positive protons in the nucleus push apart from one another. So why doesn’t the nucleus fly apart? An even stronger force—called the strong nuclear force—holds protons and neutrons together in the nucleus. You can learn more about these forces in the nucleus by watching the video at this URL:.


Q: Particles with what type of electric charges attract each other?

 Choices:

- similar

- same

- simple

- opposite

A:
opposite
