What will happen if one breeding pair of wombats is placed on a separate island with unlimited resources including no predators and plenty of food so that the wombats are able to survive?

If one breeding pair of the wombats is placed on an island with no predators, and unlimited resources, then the exponential growth of the wombats will occur on that island. The wombats will not have to struggle to find food, or keep themselves safe from the predators. There will be no threat present to these wombats. They will easily be able to breed and increase their population.

Hence, the answer is 'the population of wombats will increase exponentially'.