According to Pi, a zookeeper will know he or she has created a healthy environment for the animals WHEN THE ANIMALS REPRODUCE.
For animals to reproduce and give birth to young ones, many things has to be in place, such as suitable partners, right environment, right food, etc. Animals naturally reproduce when the environment is favorable unto them. Thus, reproduction of animals in the zoo shows that the right environment has been created for the animals.
I believe you're looking for the answer in-text citations
Answer:
I would say d
Explanation:
because you get information from the original text and summarize it