What can the rock layers tell us about life on Earth?​

Explanation:

The location of fossils in rock layers provides evidence of Earth's past landscapes. ... Scientists use a technique called radiocarbon dating to find out the age of the fossils. Once they know the age of the fossil in the rock, they also know that rock itself is about the same age!

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.