持分请教，这题咋出来的C

Hillwang

Malaria is caused by single-celled parasitic organisms belonging to the protist kingdom.
The most common organisms to cause malaria are Plasmodium falciparum, Plasmodium vivax, Plasmodium
ovale and Plasmodium malariae.
The Plasmodium life cycle takes place in mosquitos and humans. The organisms cause no negative effects to
mosquitos; in humans, however, they go through several growth stages while located in the liver cells and
red blood cells, leading to severe health effects.

The drug chloroquine was first discovered by German chemists and from the 1950s was widely used as a
successful treatment for malaria.
However, in the 1990s, health workers and scientists documented a gradual increase in the number of
malaria cases in which chloroquine was ineffective as a treatment.

Which of the following is the most likely explanation?

A. Malaria sufferers were now excreting chloroquine before it could kill the parasite.
B. Mutations conferring chloroquine resistance were now arising more frequently in Plasmodium
organisms.
C. The use of chloroquine favoured the survival and reproduction of resistant parasites.
D. A new species of Plasmodium had emerged.

Answer is C

ioioioz

我也会选c
'gradual increase'让我很快排除A D
B说now arising more frequently。为什么是现在突然变化了？有可能但是没有逻辑

dilys

这个题就是考的耐药性的问题。所以选C。

oceanflow

most likely只能是C

yutao1008

题目问的是药效为什么会减弱。A说疟疾患者排泄出chloroquine，所以chloroquine无法杀灭病菌。B讲Plasmodium里的病菌变异频繁。C说有些寄生菌体产生了耐药性。D讲一种Plasmodium种群数量变多。A和B明显不对。D从逻辑上不对，因为种群数量多并不导致药物失效。