它们被保存在自然环境中。

They are kept in their natural environment.

youdao

一个世纪之前，奥克塔维亚·希尔发起建立了国民信托组织，不是为了拯救时尚的楼房，而是“为公众永远保存自然场所之美”。

A century ago Octavia Hill launched the National Trust not to rescue stylish houses but to save "the beauty of natural places for everyone forever."

youdao

自然选择将保存重要功能的基因序列，但是其他基因会因为漂变而被改变。

Natural selection will preserve sequences with vital functions, but the rest of the genome will change because of drift.

youdao