那么，如果一个基因不再被使用，它能在一个物种中存活多久呢？
So how long can a gene survive in a species if it is no longer used?
这是一所落在遥远村庄里不再被使用的土楼。
This is one of the out-of-use earth buildings in a remote village. (This photo and caption were submitted to My Shot.)
一种用来研究偏振光下矿物的晶体结构的光学仪器，也不再被使用。
The "stauroscope", an optical instrument for studying the crystal structure of minerals under polarized light, is also no longer used.
应用推荐