Final answer:
The best answer to how animals in a zoo are influenced by their environment is 'c. Unnatural behavior', as this describes the changes in behavior patterns of zoo animals due to the artificial habitats and conditions they live in.
Step-by-step explanation:
Animals in a zoo are influenced by their environment in various ways, but the best answer to how animals in a zoo are influenced by their environment is c. Unnatural behavior. This is because zoos provide an artificial habitat that can often lead to changes in the animals' normal behavioral patterns.
Zoo animals may demonstrate behaviors not commonly seen in the wild due to confinement, lack of natural stimuli, and the presence of visitors, among other factors. Examples of such behaviors include pacing, over grooming, or changes in social structures. These alterations from what their behavior would be in a wild setting are indicative of the environmental impact zoos have on the animals.