And though the proportions of different blood types vary between human populations, scientists aren't sure why they evolved; perhaps as protection against blood born diseases, or due to random genetic drift.

虽然不同血型的比例在人群中大不相同，科学家也不能确定为什么它们会这样发展；也许是为了防止血液传播疾病，或者只是任意的基因漂流。

From Australia: To help boost Sydney Harbor's endangered seahorse population, scientists bred baby seahorses in an aquarium and built crab-trap-like undersea " hotels" to protect them as they adapt to the wild.

来自澳大利亚：为了帮助增加悉尼港濒临灭绝的海马种群，科学家们在水族馆中培育了小海马， 并建造了类似捕蟹器的海底“旅馆” 来保护它们适应野外环境。

At the time, Australia was overrun by the European rabbit— an invasive species— so, in an attempt to control the population, scientists released a virus called myxoma, which had been previously shown to be almost 100% lethal to European rabbits.

当时，澳大利亚被入侵物种欧洲兔占领， 因此，为了控制种群数量，科学家释放了一种名为粘液瘤的病毒， 此前已证明该病毒对欧洲兔几乎 100% 致死。