Answer:
during the Cambrian Period of the Paleozoic Era.
Explanation:
The Paleozoic is the earliest era (of three) of the Phanerozoic Eon and is composed of six geologic periods: the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian (in that order from earliest to the latest). Fish first appeared about 530 million years ago during the Cambrian explosion.
Phosphate Backbone is teh dna sugar phosphate bases connect with each other.
Biodiversity increases as the number of populations grow, because a greater population generally means a more diverse one.
However, this is not always true, so I'm not sure what answer they're looking for.
The chromosome must be duplicated before mitosis.
Mitosis is where a parent cell divides and produces 2 genetically indentical daughters cells. This process first requires the parent call to duplicate all of its genetic material. This ensures that the daughters cells are genetically identical to the parent cell and also the other daughter cell.
This is important because mitosis is used in many cases in living things such as growth, repair, and more. This ensures us for example not suddenly changed to another organism or another characteristic.