The fossil record provides a glimpse into the evolution of life on Earth. It shows that there have been remarkable changes in the kinds of organisms that have been abundant at different times during the past 3.5 billion years. Part A - The history of life according to the fossil record. Classify each event in the history of life into the appropriate eon or era. Drag each phrase to the appropriate bin.

Hadean eon: origin of earth

Archaean eon: oldest fossils of prokaryotic cells appear

Proterozoic eon: oldest fossils of eukaryotic cells appear

Paleozoic era: first tetrapods and insects appear

                        the cambrian explosion

Mesozoic era: dinosaurs evolve and radiate

                         origin of mammals

Cenozoic era: humans appear

                        major radiation of pollinating insects

answer; ///i do believe the answer is (virus);

c) 50% there are four chromosomes. after crossing over, 2 of the four have been changed. that means any gamete has a 2 in 4 chance or 50% chance of receiving the mutated chromosome.