Statement–Assumption — A scientist says: “Finding higher resistance in malarial parasites is significant because the analysis used modern DNA sequencing. Although the sample size was only 50, there could be no doubt about the result.” Assumptions: I. Modern techniques are more trustworthy than traditional/obsolete techniques. II. The smaller the sample size, the higher the reliability.

Introduction / Context:
The scientist expresses confidence in a result despite a small sample, citing the use of modern DNA sequencing. We must determine which background belief is required to justify that confidence.

Given Data / Assumptions:

• Method: modern DNA sequencing.
• Sample size: only 50 (acknowledged as small).
• Conclusion: “no doubt” in the result.

Concept / Approach:
The justification explicitly leans on the method’s credibility. Thus (I) is necessary: the scientist presumes modern techniques deliver higher accuracy/validity than older methods, offsetting some concerns about limited n. By contrast, (II) is the opposite of standard statistical reasoning; smaller samples usually reduce precision. The scientist never claims smaller n improves reliability; therefore II is not implicit.

Step-by-Step Solution:
1) Link confidence to method quality: modern DNA sequencing → higher trust → supports “no doubt.”2) Reject II: it contradicts statistical principles and is not suggested by the statement.

Verification / Alternative check:
Even when asserting strong confidence, researchers typically invoke superior methodology, not the virtue of small samples.

Why Other Options Are Wrong:
“Only II,” “either,” or “both” mischaracterize the role of sample size; “neither” ignores the explicit method-based confidence.

Common Pitfalls:
Assuming the speaker endorses all implications of what is mentioned (e.g., small sample → better) rather than the specific rationale offered (method quality).

Final Answer:
if only assumption I is implicit.