本题目来源于试卷: SL Topic C3.2 Defence against disease，类别为 IB生物学
[问答题]
e. A single vaccination is 93% effective ac)gui9:tya*bla ; tf8qf2k2i n p0ndl6 ;8rg0cr3l rfxd two vaccinations given six months apart are 97% effective in producing immunisation. (Source – Center for Disease Control, Atlanta, USA, 2014 figures). E6 ;8flrcdp0 r0rxn3lg xplain why a second vaccination can increase the effectiveness of immunisation.
参考答案: The first vaccination causes an immune response, the production of antibodies.
The first vaccination causes production of memory cells.
The second vaccination causes an increased reaction of the memory cells/ very rapid production of antibodies and more memory cells. Increased production of antibodies/memory cells lessens the chance of future infection.
本题详细解析:
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