SAT 语法题一道09年1月 section 6第3题With the popularity of travel and

SAT 语法题一道
09年1月 section 6第3题
With the popularity of travel and tourism reaching unprecedented heights, environmental damage to previously unspoiled sites and remove wilderness areas (is becoming pervasive, irreversible, and) costly.
为什么括号里的部分是对的?! 为什么and 前面有逗号?!