1.Throughout the Paleozoic, sea level was variable; sometimes it was high and other times it was low. What was the primary cause of this variation in sea level? 2. What was the coldest period of the...

1.Throughout the Paleozoic, sea level was variable; sometimes it was high and other times it was low. What was the primary cause of this variation in sea level? 2. What was the coldest period of the Paleozoic? What may have contributed to this cooling period? 3. During the Silurian, many continental landmasses were covered by shallow seas. Yet this time period marks the emergence of land plants. How can this be?