Try reading the book recommended for COIS 5310.
The taskbar is used to display the programs that are currently in use and the active applications are the ones that you're using and is displayed on the taskbar.
The relationship between active application and the task bar is that all the active applications are shown on the taskbar.
A macro virus takes advantage of the relationship between the trust application and the operating system?
System program mostly refers to base program on which application program is running on! Priority is for system program! For better understanding I'll can give you examples Operating System(OS), Compiler, assembler are System program Media players, word processors and almost all that we use often are application programs
An active application is shown in the task bar.
the relationship between a scientific investigation and a scientific knowledge is that they lead to constantly changing.
http://www.webopedia.com/TERM/A/Application.html
database
No, this is a common misconception. The application layer is the interface between programs (applications) and the network layers.
Databases are independent of the applications that use the data.
Application layer is a component of the OSI model of computer communication. Application software is programs that run on computers so that you can "do something" such as write a document.
System Programs or System Software are the programs which enable the computer hardware or system to run (without these the computer as a whole or parts of it's functionality would not work). Examples include the operating system, device drivers. Application Programs or Application Software are the programs written to for specific applications or execution of specific tasks. e.g. Microsoft Word is an application software for word processing. Internet Explorer and Mozilla Firefox are application software written for internet browsing. Computer games are also application programs.