The climate impact of the average bag of prepared salad is sky-high due to all of the fertilising, artificial heating, packaging, storage and transport it requires. (From BBC, 4 January 2009: Foraging for food)

成品沙拉对气候的影响极大，因为它在整个制作过程中需要施肥、人为加热、包装、储存、运输。食品约占英国碳排放量的五分之一。

1、sky-high，极高。

2、施肥、加热、包装用动名词，储存、运输用名词形式。有什么讲究吗？

3、prepared salad前没有冠词。