Automatic fire dampers in ventilation systems are operated by use of（）.

A.remote operated valve
B.fusible link
C.CO₂ system pressure switch
D.heat or smoke detector

A.accumulation of carbon dioxide gas that chokes the battery
B.accumulation of explosive and toxic gases the battery can generate
C.mildew or dry rot in the battery box
D.battery failure including battery case meltdown caused by excessive heat

A.Paints，varnish，or other liquid flammables are stowed in a dry stores locker
B.Inert cargoes such as pig iron are loaded in a wet condition
C.Oily rags are stowed in a metal pail
D.Clean mattresses are stored in contact with an electric light bulb