设圆x²＋y²＝1的一条切线与x轴、y轴分别交于点A、B，则线段AB长度的最小值为________．

Basically, a firewall is a (71) process or a set of integrated processes that runs on a router or (72) to control the flow of networked application traffic (73) through it. Typically, firewalls are placed on the entry point to a (74) Network such as the Internet. They could be considered traffic cops. The firewall’s (75) is to ensure that all communication between an organization’s network and the Internet conform to the organization’s security policies.

（71）处填（）。

A．dependent

B．isolated

C．related

D．standalone