What were interests of early civilizations as they studied the ocean?

Seed plants that lived during the carboniferous impact life on earth today because a. they are the ancestors of all plant life on earth. b. their remains formed coal, which is an important resource. c. they produced fossils that are used to date many geologic events. d. their presence caused oxygen levels to drop, allowing animals to evolve.

Which of the following terms describes the layers of air surrounding the earth ?

What would have happened to portugal’s trade if they had not found a way to sail around the tip of africa