Statement: In a non-immunised child, if the body loses the war against the polio virus, the virus is carried by the blood to the nervous system; when the nervous system loses, the nerves controlling muscles are destroyed, causing paralysis. Conclusions: I. Strong, well-executed immunisation programmes are likely to reduce polio cases. II. In a non-immunised child, there are no antibodies to restrict the virus attack inside the body.
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AIf only conclusion I follows
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BIf only conclusion II follows
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CIf either I or II follows
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DIf neither I nor II follows
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EIf both I and II follow
Answer
Correct Answer: If only conclusion I follows
Explanation
Introduction / Context:The statement narrates the pathogenesis of polio in a non-immunised child leading to paralysis when the body and nervous system fail to contain the virus. We must determine which conclusions logically follow from this medical description.
Given Data / Assumptions:
- Non-immunised → higher risk of systemic spread and neuronal damage.
- Immunisation is standard preventive strategy, though the mechanism is not detailed here.
- No explicit claim is made about absence of all antibodies in non-immunised children.
Concept / Approach:Conclusion I follows: if lack of immunisation enables viral advance culminating in paralysis, then effective immunisation campaigns are likely to reduce cases by pre-arming the immune system. Conclusion II overreaches: “no antibodies” is an absolute biological claim not stated; even non-immunised individuals can have innate or cross-reactive responses. The text does not say “no antibodies,” only that the body loses the war, hence II does not follow.
Step-by-Step Solution:1) Map causal chain: non-immunised → higher vulnerability → paralysis risk → supports I (prevention via immunisation).2) Check for absolutes: “no antibodies” not asserted → II does not follow.
Verification / Alternative check:Even if some antibodies exist, failure can still occur; conclusion II’s absolutism is unnecessary and unsupported.
Why Other Options Are Wrong:“Both/Either” accept an extreme claim; “Neither” ignores the clear preventive implication.
Common Pitfalls:Equating “not immunised” with “immune response impossible.”
Final Answer:If only conclusion I follows.