阐述尿嘧啶修复系统修复的主要步骤，并列出这一修复系统所需要的酶。

Diagram the steps executed in the uracil repair system that are UNIQUE to this repair system.

阐述尿嘧啶修复系统修复的主要步骤，并列出这一修复系统所需要的酶。

Diagram the steps executed in the uracil repair system that are UNIQUE to this repair system. Provide names for the enzymes used.

污染治理对策应以生态系统修复为根本，控制陆源污染物为前提。

Eco-system remedy and controlling land sources pollution is the basic countermeasures of pollution treatment.

污染治理对策应以生态系统修复为根本,控制陆源污染物为前提.

Eco - system remedy and controlling land sources pollution is the basic countermeasures of pollution treatment.