Taking into account all these arguments, I also think, like many people, that keeping animals in zoos is cruel and unnecessary.

taking 是动词 take 的现在分词形式，take 的基本意思是"拿、取"。 into 是介词，表示"进入...状态"或"转变为..."。 account 是名词，意思是"考虑、计算、账目"。 taking into account 是一个固定短语，字面意思是"把...纳入考虑"，即"考虑到..."的意思。这个短语中 taking 是现在分词引导的短语作状语，into account 表示"进入考虑范围"。