Fill in each blank with one suitable word. Man first (1) on earth half a million years ago. Then he was little more than an animal; but early man had several big advantages (2) the animals. He had a large (3), he had an upright (4), he had clever hands; and he had in his brain special groups of nerve cells, not (5) in animals, that enabled him to invent a (6) and use it to communicate with his fellow men. This ability to speak was of very great (7) because it allowed men to share ideas, and to plan together, so that tasks impossible for a (8) person could be successfully undertaken by intelligent team-work. Speech also enabled ideas to be (9) on from generation to generation so that the stock of human knowledge slowly increased. It was these special advantages that put men far (10) of all other living creatures in the struggle for (11). They can use their intelligence (12) their difficulties and master them.