Question

why did many plants in australia become extinct? rabbits were underpopulated rabbits were endangered rabbits were overpopulated rabbit populations declined

Explanation:

Rabbits are an invasive species in Australia. When their populations exploded (overpopulated), they overgrazed vast areas of native vegetation, destroying the habitat and food sources for many native plant species, leading to some plant extinctions. The other options describe rabbit population trends that would not cause widespread plant loss.

Answer:

rabbits were overpopulated