Correct the mistakes, if any, in sentences 1-6. Answers in the next chapter.
1. There is still disagreement over if vitamin C can prevent colds.
2. A number of different hypothesis have been put forward.
3. A large amount of theories have been disproved.
4. Current research seem to suggest that this is an isolated phenomena.
5. The available evidences tend to refute those claims.
6. The next section considers the issue of whether or not voting should be mandatory.