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.

The correct statement which describes that marsupials are found in North America and Australia, but they would not have been able to swim across the ocean because the continents were once connected and the marsupials were able to migrate over the land. The latest research about the tectonic models proved that the the continent North America and Australia were connected more than a billion years ago.

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.

the principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to test the hypothesis, and development of a conclusion that confirms, rejects, or modifies the hypothesis.