问题: Antibodieswereproducedwhen_____.
A: inheritedimmunityandacquiredimmunity
B:theantigenisintroducedintothebody
C:acquiredimmunity
D:specifiedimmunity
E:antigensvaryintheirchemicalstructure.
F:Thekindofantigenthatcauseditsproductionandnoother.
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