What does na+ represent? select all that apply.
a positively charged sodium ion
a sodium ion that has lost an electron
a negatively charge sodium ion
a sodium ion that has gained an electron
a neutral sodium atom

Which of the following statements is most likely correct about a rock belonging to the jurassic age and a rock belonging to the cambrian age? options: 1) they have identical fossils of organisms that have evolved over time. 2) both have animal fossils preserved in them due to weathering and erosion. 3) they contain different fossils because life on earth has changed through time. 4) the fossils in them were formed on the surface of earth due to exposure to sunlight.