<span>Na+, cl-, hco3-, and k+ are electrolytes. Na+ is sodium. Cl- is chloride. Hco3- is bicarbonate and k+ is potassium. Electrolytes are needed for our organs and cells to function like they should. We obtain some of these electrolytes through the food we eat, such as sodium from salt and potassium from bananas.</span>
Scientists use fossils to learn about organisms' lives and evolutionary relationships, to understand geological change, and even to locate fossil fuel reserves.
