Even though intelligence may be quite (i)____________, and even though scientists may have made frustratingly (ii)____________ progress in understanding it, many experts on intelligence still think that the potential (iii)____________ of the quest to understand intelligence make it worth continuing. For instance, a brain-based understanding of intelligence may help teachers design strategies for educating children more effectively. A. useful B. little C. intellectual impediments D. neglected E. rapid F. practical values G. complex H. extensive I. financial rewards