Answer: This would be an example of mutualism.
Explanation: Mutualism is when, in a certain situation, benefits both organisms. The gazelles and ostritches in this situation are both watching for predators and are making sure to alert each other to the danger that could spring nearby. Both of these animals can locate predators in different ways. Ostritches are capable of seeing predators from in the tall grasses, while the gazelles are able to hear predators with their great hearing. Together, these two creatures make a great defense. Both the gazelles and ostritches benefit. This is known as mutualism.