Question

a scientist is studying the fossil records of organisms in an attempt to explain how the distribution of ecosystems has changed over time. he notices that fossils on the coast of south america are very similar to the fossils in africa. however, the organisms that resemble the fossils are still alive in africa but not in south america. which of the following best explains the findings of the scientist? continental plates shifted, and environmental factors are different. large extraterrestrial objects hit earth, and the environment became different.

Explanation:

The theory of continental drift suggests that continents were once joined and have since moved apart. Similar fossils on South America and Africa imply a past connection. The difference in current - day organism presence (alive in Africa but not South America) can be due to environmental changes after the continents separated. Continental plate shifting (part of plate tectonics) and subsequent different environmental factors (like climate, available resources) can lead to such a situation. A large extraterrestrial hit would likely have more widespread and catastrophic effects that are not indicated by the fossil - organism distribution described.

Answer:

Continental plates shifted, and environmental factors are different.