What is characteristic of low order damage in explosions?

Low order damage in explosions is characterized by damage that is generally less extensive compared to high order explosions. The correct choice highlights features such as walls bulging outward and roofs remaining somewhat intact. This suggests that the explosion's pressure was significant enough to cause some distortion and movement in the structure, but it did not lead to total destruction or fragmentation.

In low order explosions, the force generated is typically enough to create significant damage but not powerful enough to completely demolish the building or structure. Walls may bulge due to the pressure exerted by the explosion, which can force them outward, while roofs might still be held in place, indicating that the structural integrity, at least to some extent, was maintained.

The other options represent more severe types of damage typically associated with high order explosions, where complete destruction or widespread scattering of debris occurs, which indicates a greater release of energy than what is typically found in low order explosions. Consequently, the choice reflecting the bulging of walls and partially intact roofs precisely encapsulates the kind of damage that characterizes low order explosions.