Based on sentence fluency, transitions, and writing conventions, which conclusion most needs revision? Finally, scientists continue to argue their cases for and against a manned mission to Mars. However, an eventual mission seems likely.

In the end, there are logical pros and cons for a manned mission to Mars. It seems its more a matter of when it will happen than if it happens.

In conclusion, there are good arguments for and against a manned mission to Mars. But based on the evidence, it seems as though a manned mission is likely.

Overall, scientists continue to debate the pros and cons of a manned mission to Mars. Yet despite their indecision, it seems almost certain that a mission will happen.