Explanation

The correct sequence to arrange the words in a meaningful order for constructing a building is:

4, 2, 1, 5, 3, 6

This sequence represents the following steps:

1. Foundation (4): The first step in building is to lay the foundation.
2. Walls (2): Once the foundation is set, the walls are constructed.
3. Windows (1): After the walls, windows are installed.
4. Roof (5): The next step is to add the roof.
5. Floor (3): The floor is typically installed next, though this can vary.
6. Room (6): Finally, the room is completed.