A、They can not accomplish their daily tasks. B、They suffer injuries from less amount of sleep. C、They get no damage in their per

M: Some people seem to need significantly less sleep than others.
W: Tell me about it. I have a friend who swears that she sleeps only five hours a night. She seems to have plenty of energy, and she’s not confused and incompetent the way I am after several nights of only five hours of sleep.  You know what really annoys me? Because she sleeps less, (23) she has more time to accomplish more in her days than I do. It’s not fair.
M: I know what you mean.  I’ve also heard scientists have discovered a gene in flies that determines how much rest the individual needs. Flies with a version of this gene are actually programmed to need less sleep than others.  (24) And we humans possess a similar gene.
W: So the amount of sleep one needs seems to be genetically inherited?
M: Yes. And (25) families of flies with a lower sleep requirement don’t seem to suffer any injuries in their performance of daily tasks. It may very well be that people who claim to need less sleep to operate normally are telling the truth.
W: That’s depressing.
M: Well, you might be interested to know that flies programmed to sleep less tend to die earlier.
W: Really? So maybe I’ll end up with the same hours of waking time as my friend after all. It’ll just take me a few extra years of living to catch up with her!
M: Maybe.