Answer:
Option A, hat organisms have changed over time
Step-by-step explanation:
Here option B is incorrect as Cenozoic Era came after the Paleozoic Era.
Option C is also incorrect because Cenozoic Era is the most recent era while Paleozoic Era is the oldest.
Option D is incorrect as it is visible from the graph the animal species on planet earth have changed a lot from Paleozoic Era to Cenozoic Era
Thus, the only correct answer is option A, as it is clearly visible from the graph that organisms have changed drastically over time on planet earth.