Why can two dangerous goods, each individually low-risk when stowed alone, still require segregation from each other under the IMDG Code?

A. Segregation rules apply only to substances that are independently high-risk, never to combinations

B. Certain combinations of substances can react dangerously with each other even if each is comparatively benign in isolation (e.g. an oxidiser reacting with an otherwise stable organic substance) — segregation tables account for these interaction risks specifically, not just each substance's standalone hazard rating

C. Segregation exists only to simplify the stowage plan, with no genuine chemical basis

D. Segregation requirements are identical for all dangerous goods, so this scenario cannot occur

A. Only the Chief Engineer needs to consider this, never the deck watchkeeper

B. None — stability is fixed regardless of loading

C. Increased displacement generally raises the centre of gravity if weight is added high up, and free surface effects in partially-filled tanks can reduce the effective metacentric height (GM)

D. Additional weight always improves stability regardless of where it is placed

A. This only matters when the vessel is at anchor

B. Negligible — watertight doors below the waterline are rarely closed anyway

C. Only relevant if the vessel carries passengers

D. Significant — a failed watertight closure compromises the subdivision the vessel's damage stability calculations rely on, potentially allowing progressive flooding between compartments in the event of damage