form an important art of the colorful signals

       used by many animals.  Animals acquire

Line       carotenoids either directly (from the plants

  (5)      and algae that produce them) or indirectly (by

eating insects) and store them in a variety of

tissues.  Studies of several animal species

have shown that when choosing mates, females

prefer males with brighter carotenoid-based

 (10)      coloration.  Owens and Olson hypothesize that

the presence of carotenoids, as signaled by

coloration, would be meaningful in the context

of mate selection if carotenoids were either

rare or required for health.  The conventional

 (15)      view is that carotenoids are meaningful

       because they are rare:  healthier males can

forage for more of the pigments than can their

inferior counterparts.  Although this may be

true, there is growing evidence that carotenoids

 (20)      are meaningful also because they are required:

       they are used by the immune system and
                    for

       detoxification processes that are important

for maintaining health.  It may be that males

can use scarce carotenoids either for immune

 (25)      defense and detoxification or for attracting

females.  Males that are more susceptible to

disease and parasites will have to use their

carotenoids to boost their immune systems,

whereas males that are genetically resistant

 (30)      will use fewer carotenoids for fighting disease

and will advertise this by using the pigments

for flashy display instead.

Q13:

Information in the passage suggests that which of the following is true of carotenoids that a male animal uses for detoxification processes?

1. They were not acquired directly from plants and algae.
2. They cannot be replenished through foraging.
3. They cannot be used simultaneously to brighten coloration.
4. They do not affect the animal’s susceptibility to parasites.
5. They increase the chances that the animal will be selected as a mate.

Answer:

这道题有争议，C  & E, 开始我选择E, 但现在又感觉选择C，
                因为Males
                that are more susceptible to
                disease and parasites will have to use their
                carotenoids to boost their immune systems,
                whereas males that are genetically resistant
                will use fewer carotenoids for fighting disease
                and will advertise this by using the pigments
                for flashy display instead.
                说males that are genetically resistant
                will use fewer carotenoids for fighting disease，而是using the pigments
                for flashy display instead，也就说
                用来
                fighting disease的carotenoids和用来brighten coloration
                不是兼容的，不知道我的分析对不对，请高人指教。

我认为选C, E的表述中缺陷是 用于解毒的色素增加了被择偶的几率, 但是没说色素是否足量用来保持健康

Csimultaneously 逻辑严密

"...will use fewer carotenoids for fighting disease and will advertise", fewer indicates that once being used to fight disease, carotenoids can't be used as coloration any more.