The majority of visitors _____ in favor of his conclusion that the number of books published on the subject _____ simply surprising.

A．were; was

B．was; was

C．were; were

D．was; were

现有一生活污水净化处理系统，处理流程为“厌氧沉淀池→曝气池→兼氧池→植物池”。其中植物池中生活着水生植物、昆虫、鱼类、蛙类等生物。污水经净化处理后，可用于浇灌绿地。回答问题：

污水流厌氧沉淀池、曝气池和兼氧池后得到初步的净化，在这个过程中，微生物通过（）呼吸将有机物分解。