Answer:
d. sustainable
Step-by-step explanation:
The wild populations of animals and plants are considered sustainable natural resources since a controlled exploitation of these species may ensure their continuity in nature. For example, habitat fragmentation is one of the major causes of a reduction in the population size of the cheetah as they need a large territory. However, the protection and conservation of natural habitats of Cheetah ensure that the species is not extinct in the near future. Therefore, the cheetahs are a sustainable natural resource.