Autonomous organisms on our tree of life cannot be much smaller because they must contain protein-building cellular structures called ribosomes, which are each about 20 to 30 nanometers across.

• 但是在我们生命活动中的有机体并没有那么小，因为我们身体里有一种结构叫做核糖体，是合成蛋白质的场所，在合成蛋白质的时候经常聚集要聚集20-30个一起工作。