Population ____1____ is one of the most serious problems of the world today. Studies ____2____ in this area suggest that the world population is further likely to increase by a few more billions. According to many environmental scientists, ecologists, researchers, and other intellectuals, the rise in the population will lead to several ____3____ consequences. Most significantly, the increasing number of people will ____4____ more water, more food, and more energy ____5____ to survive.
Choose the word which fits in the blank labelled 4 and gives appropriate meaning.

1. A
   prevent
2. B
   not require
3. C
   require
4. D
   ignore