The dinosaurs probably became extinct after a giant asteroid hit the Earth about 65 million years ago. But what (HAPPEN) if this asteroid (MISS)? Scientists believe that in this case, dinosaurs (CONTINUE) to dominate the Earth, and that modern animals (PROBABLY EXIST). Instead of elephants and lions and so on, there (BE) different types of dinosaurs, because the animals we have now simply (BE ABLE) to evolve. Some scientists have even suggested that dinosaurs (DEVELOP) along the same lines as human beings, but this is a minority view. The general view is that perhaps dinosaur brains (GROW) larger, but if they (EXIST) today, dinosaurs (CHANGE) very much in general, and (LOOK), much the same. The prospects for human beings would not be so good, however. If the asteroid (COLLIDE) with the Earth, there (PROBABLY BE) any humans alive today. When the asteroid disaster wiped out the dinosaurs, it gave mammals the advantage. Without that space collision, mammals (STAND) much chance against the dominant dinosaur species.