Iron and zinc are two kinds of indispensable trace elements of fish.

铁和锌是鱼类非常重要的两种必需微量元素。

youdao

Cu, Zn, Co and Ni are indispensable trace elements in human body, which are all transition elements. They serve as important active sites of enzymes, and have good antibacterial activities.

铜、锌、钴、镍是过渡元素，是人体中不可缺少的微量元素，是一些重要酶的活性中心，且均有良好的抑菌活性。

youdao

Cu, Zn, Co and Ni are indispensable trace elements in human body, which are all transition elements. They serve as important active sites of enzymes, and have good antibacterial activities.

铜、锌、钴、镍是过渡元素，是人体中不可缺少的微量元素，是一些重要酶的活性中心，且均有良好的抑菌活性。

youdao