Conversely, on some worlds of the superbreathers, when the planet is not too large, it is sometimes expedient to provide for a mortal type which can readily negotiate atmospheric passage.

• 相反地在一些低呼吸者世界上，当行星也不是巨大的时候，它有时是提供一个适宜人类类型能够容易克服的大气压通行。