Statement:\nIn 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.\n\nConclusions:\nI. Strong, well-executed immunisation programmes are likely to reduce polio cases.\nII. In a non-immunised child, there are no antibodies to restrict the virus attack inside the body.

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.