Interaction & Interdependence C.7 Defence Against Disease (id: bd7997353)

本题目来源于试卷: Interaction & Interdependence C.7 Defence Against Disease，类别为 IB生物学

[单选题]
The graph shows how the number of antibodi3 jp5w:z yec(.djfiq 3es changed in an individual's blood(.rjy. 0vsoub 1uhc7l oveb1.v o u0u( 7ly.cjshrr time.

What is the most likely cause of the change in antibody levels at point X?

A. Primary infection
B. Secondary infection by the same pathogen
C. Infection by a different pathogen
D. Infection by a different pathogen


参考答案:  B


本题详细解析:

Explanation​:

A second infection by a pathogen triggers a much faster and more potent immune response, resulting in the production of greater levels of antibodies (Choice B), when compared to primary infection. Primary infection causes a smaller increase in antibody numbers; this is represented by Y (Choice A). Infection by a different pathogen (Choice C) would cause a raise in antibody numbers similar to levels in point Y. Antibiotics do not increase antibody numbers (Choice D).

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