共生关系
参考答案：
两种不同生物紧密相联地生活在一起成为互惠互利的关系。
影响产品质量的因素有（）个。
Because Web servers are platform and application (60) ，they can send or request data from legacy or external application including database．All replies，once converted into (61) mark up language，can then be transmitted to a (62) ．Used in this way，Intranets can (63) lower desktop support costs，easy links with legacy application and databases and， (64) all。ease of use．
64（）
A．abort
B．about
C．above
D．around
