Direction: In the following passage, some of the words have been left out. First read the passage over and try understand what it is about. Then fill in the blanks with the help of the alternatives given.

Twenty million years ago, our immediate ancestors probably still lived in the trees. After we came (451) from the trees, we evolved an upright (452); our hands were more useful, being (453).We possessed agility and an excellent binocular (454). We had, in course of time, (455) many of the preconditions required for (456) tools. Moreover, there was now a real (457) in possessing a large brain and (458) communicating complex thoughts. Anyway, other things (459) equal, it is better to be smart (460) to be stupid.