How would you describe color to a blind person?

You can use their sense of hearing.

For example, Blue could represent the waves or something cold so you could let them hold something cold and let them hear the ocean's waves at the beach.

an ion is a charged atom or molecule. it is charged because the number of electrons do not equal the number of protons in the atom or molecule. an atom can acquire a positive charge or a negative charge depending on whether the number of electrons in an atom is greater or less then the number of protons in the atom.

b would be the answer