Final answer:
The similar appearance between Australian marsupials and respective placental mammals, despite independent evolution, is an example of convergence. The correct option is B.
Step-by-step explanation:
The phenomenon where species that have evolved independently resemble each other due to similar environmental pressures is known as convergence.
In the context of Australian marsupials, they have evolved characteristics similar to those of respective placental mammals, despite their separate evolutionary pathways.
This is because they have been subjected to similar ecological roles and selection pressures, which have resulted in convergent evolution.
Examples like the marsupials in Australia, such as kangaroos, show similar niches to placental mammals found in other parts of the world, highlighting this pattern of convergence. The correct option is B.