Well, one reason is that there are developmental disorders that seem to involve damage to one system but not to another.

一个原因是,发展障碍看上去,只会对某一个系统产生损害,而不会损害其他系统

耶鲁公开课 - 心理学导论课程节选

The reason is that because of the ways that different microorganisms take the ways the different microorganisms reproduce and damage cells and tissue within your body, you need different ways to respond to them effectively.

因为不同的微生物以不同的方式,以不同的方式繁殖,和损害体内的组织和细胞,你需要多种有效的免疫反应来对付它们

耶鲁公开课 - 生物医学工程探索课程节选