In the 1960s, Cosmic Microwave Background Radiation was discovered by the invention of radiotelescopes. This CMBR is now known

to be

solar radiation

static interference

left over heat from the big bang

an unidentified response from alien life.

explanation: no but i do not usually comment

nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.