单项选择题

Tuberculosis is highly infectious because ______.

A．spores are resistant to drying
B．the causative organism is encapsulated
C．droplets of sputum remain infective for a long time due to the resistance of the organisms to drying
D．none of these

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热门试题

单项选择题

According to the passage, the risk of infection from airborne microorganisms would likely be greater during a ______.

A．heat wave
B．time of high humidity
C．windless period
D．shortage of fuel oil

单项选择题

The passage uses the term vegetative forms to refer to ______.

A．Plants that infest human habitations
B．the fact that bacteria are really vegetables
C．the growing stage of the bacteria as opposed to the dormant stage
D．the difficulty in classifying the types of bacteria