生物与其生存环境之间相互作用的变化所导致的部分或整个生物群体遗传物质的一系列不可逆转的改变，这是指（)。
参考答案：生物进化
班长职责是什么？
The pollution question as well as several other issues is going to be discussed when the Congress is in ______ again next spring.
A. assembly B. conference C. convention D. session
