0n the fully containerized ship, approximately one-third or more of the cargo is on deck above the rolling center. Top stowed containers are subject to（）.

A.help keep the deck dry
B.prevent stress concentrations on the stringer plate
C.protect against twisting forces exerted on the frame of the vessel
D.reinfo ce th eside stringers

A.as it warms up it becomes heavier than air
B.the way it reacts with sea water
C.the strong odor it produces
D.its low temperature causes frostbite or freezing

A.PV valves
B.warning signs
C.flame screens
D.stop-check valves