Question

marsupials are found in north america and australia, but they would not have been able to swim across the ocean. according to scientists, how did this group of organisms come to live on two separate continents?
marsupials used to have adaptations that allowed them to swim but lost these adaptations over time.
the two groups of marsupials evolved independently of one another on two separate continents.
the continents were once connected, and marsupials were able to migrate over the land.
the oceans were shallow in prehistoric times, which allowed the marsupials to travel from one continent to another.

Explanation:

• The theory of continental drift suggests that continents were once connected (as part of a supercontinent like Pangaea). This would have allowed land - dwelling organisms like marsupials to migrate across the landmass.
• Marsupials not being able to swim across the ocean rules out options like swimming adaptations (if they lost them, they still couldn't have crossed the ocean initially) and shallow oceans (as they couldn't swim). Also, the idea of independent evolution of the same group (marsupials) on two separate continents is less likely compared to the continental - drift - based migration explanation.

Answer:

The continents were once connected, and marsupials were able to migrate over the land.