A study аt оne prisоn shоwed thаt owning а pet can change a hardened prison inmate into a more caring person. Another study discovered that senior citizens, both those living alone and those in nursing homes, became more interested in life when they were given pets to care for. Even emotionally disturbed children have been observed to smile and react with interest if there is a cuddly kitten or puppy to hold. Animals, then, can be a means of therapy for many kinds of individuals. Which of the following sentences from the above passage would be considered the topic sentence of the passage