Which era is referred to as "The Age of Fishes"? Why does this era have this distinction?

Aeukaryotic cell must be from a plant if the cell a) a nucleus b) a nuclear envelope c) cytoplasm d) a cell wall

Are the earth's ocean floor and continents the same age geologically? why or why not?

An ecologist studied the same species of deer during the summer and the winter. she noticed that during the summer, when there was plenty of food, the deer were energetic and playful. however, during winter when food was scarce, the deer moved more slowly and did not run unless they needed to escape a predator. which scientific fact is best supported by her observations?