Arrange building elements in a construction-reasonable order: 1) Window 2) Foundation 3) Floor 4) Ventilator 5) Roof

Introduction / Context:
We select a coherent order given only these items (walls, etc., are omitted in the options).

Given Data / Assumptions:
Foundation precedes superstructure; basic flooring preparation comes early; openings (windows/ventilators) are fitted before final roofing in this simplified sequence.

Concept / Approach:
Start from base, then internal surface, then openings, and finally the covering.

Step-by-Step Solution:

Verification / Alternative check:
Among the given choices, this is the most construction-plausible flow.

Why Other Options Are Wrong:
They start with floor before foundation or place windows before base—logically inconsistent.

Common Pitfalls:
Assuming missing items (walls) must appear; stick to given elements.

Final Answer:
2, 3, 1, 4, 5