Confused with the metrics in different monitors

Hi,

I've created three monitors: Apache, Tomcat and Linux (all location on the same machine) where my web application is residing. I've viewed the reports for all the monitors, and I'm a little confused with some of the metrics on the reports.

1. What is the difference between Response Time under Linux and Response Time under Apache?
2. What is the difference between CPU under Linux and CPU under Apache?
3. What is the difference between Request Per Min under Tomcat, and Request Per Min under Apache?
4. What is the difference between Busy Servers under Apache and Busy Threads under Tomcat?

Would appreciate if anyone could help clarify this for me. Thanks!