（新概念）第20课：and having different effects为什么effects是复数形式?

题目

（新概念）第20课：and having different effects为什么effects是复数形式?
It did not; some snakes manufacture a poison different in every respect from that of others,as different as arsenic is from strychnine,and having different effects.One poison acts on the nerves,the other on the blood.
1.辅导翻译成“不同毒蛇的毒液产生的效果不同,”为什么是“不同毒蛇的毒液”?哪来的?
2.and having different effects为什么effects是复数形式?
前面manufacture a poison 中的poison是单数,怎么后面变成effects复数了?having different effects的主语是什么?

答案