Question

Which of the following is not necessarily correct in the context of the passage?

• A. On the basis of evidence found on Mars scientists have confirmed that ingredients for life once existed on Mars.
• B. NASA's rover Curiosity landed on Mars near Gale Crater.
• C. Drinkable water flowed through Yellowknife Bay once.
• D. Scientists are not sure if organic compounds existed on Mars.

Hint:

When the passage uses cautious words like "likely," "may," or "suggests," avoid treating them as absolute facts in inference questions.

Answer 1

The Correct Option is C

Step 1: Analyze each statement with reference to the passage.
- (a) The passage clearly states that scientists found irrefutable evidence that Mars once had the ingredients for life (minerals, sulphates, clays, etc.). Hence, (a) is correct.
- (b) The Curiosity rover indeed landed inside Gale Crater, located near the Martian equator. This is correct.
- (c) The passage says: "The water that once flowed through the area known as Yellowknife Bay was likely drinkable." The keyword is "likely," meaning it is not a certainty, only a probability. Thus, saying it definitely flowed as drinkable water is not necessarily correct.
- (d) The analysis "stopped short of a confirmation of organics," meaning scientists are not yet sure about organics. This is correct. Step 2: Conclusion.
Since the certainty of (c) is doubtful ("likely" not "confirmed"), it is the one that is not necessarily correct. \[ \Rightarrow \boxed{(c)\ \text{Drinkable water flowed through Yellowknife Bay once.}} \]

Answer 2

Scan the passage for certainty markers — words like "irrefutable," "confirmed," "likely," or "stopped short" — and match each option against the exact strength of claim the passage supports, rather than paraphrasing the passage narrative.

1. Option A: the passage uses strong, confirmed language ("irrefutable evidence") for the presence of past life-supporting ingredients on Mars, so this statement is fully backed and therefore correct as given.
2. Option B: the landing site detail (Curiosity near/inside Gale Crater) is stated as plain fact with no hedging in the passage, so this statement is also correct as given.
3. Option C: the passage specifically hedges this claim with the word "likely," meaning the drinkability of the past water is a probability, not a certainty; stating it as a flat fact overclaims what the passage actually supports.
4. Option D: the passage explicitly says the analysis "stopped short of confirmation" regarding organics, so uncertainty about organics is directly and correctly reflected here.

Since only option C upgrades a hedged, probable claim into an unqualified certainty, it is the statement that is not necessarily correct.

Hence, the correct answer is Drinkable water flowed through Yellowknife Bay once.