Listen to the passage and answer the three related questions. To access the questions, click on 1, 2 and 3 respectively. After reading the four choices, click on the response that best answers the question. The following is an example: - Language is said to be one of the factors that differentiates humans from animals, but new research shows that animals use language as well. In today's program, we'll discover how ethologists are able to teach chimpanzees and gorillas sign language, and how Rhesus monkeys emit different alarm calls to identify predators. You may already know that songbirds alert each other with hundreds of different songs, but did you know that whales may know how to rhyme? Even elephants, giraffes and hippos, animals that were once considered to be virtually silent, communicate with sounds inaudible to the human ear. Join us on this fascinating journey! What is this program trying to illustrate? Выберите один ответ: a. There is no substantial difference between humans and animals. b. Evidence shows that most animals are capable of logic. c. Like humans, all animals can be taught sign language. d. Animals are capable of more elaborate communication than previously thought.