What suggests that the earliest movement of animals onto land occurred as short visits?

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The movement of modern fishes, annelids, molluscs, and arthropods onto land suggests that the earliest movement of animals onto land occurred as short visits. This is because these animals are all able to survive on land for short periods of time, but they cannot reproduce on land. This suggests that the earliest animals to move onto land were not able to establish permanent populations on land, and that they only visited land for short periods of time.

What Suggests That the Earliest Movement of Animals onto Land