What does the ESC key do?
It is used to cancel an operation in progress.  It also cancels a command.

What does the  Backspace key do?
It deletes text to the left of the insertion point.

What does the Ctrl (Control)  key do?
A key you press in combination with other keys to perform a command or make a selection within an application (software program)

What does the Alt key do?
It is a key you press in conjunction with another keyboard key to run a macro or execute some type of operation.  For example, you can use the ALT + F to open a file within a wordprocessing software like Microsoft Word.

 You can also use the Alt key in conjunction with the Function keys at the top of the keyboard to perform a command or action.

 What does the Delete key do?
It deletes text to the right of the insertion point. 

 What does the Insert key do?
Used to add or move text into existing text.  Text that already exists moves to the right when additional text is inserted using the Insert key.

What does the  Home key do?
Use the Home key to naviagate or move in programs.  Pressing it within a wordprocessing program such as Microsoft Word will move your cursor/insertion point  to the beginning of a line. 

 Pressing CTRL + Home will move your insertion point to the beginning of a document.

 What does the End key do?
Use the End key to navigate or move in programs.  Pressing it within a wordprocessing program such as Microsoft Word will move your cursor/insertion point to the end of a line. 

 Pressing CTRL + End will move your insertion point to the end of a document.

 What is the Page Up key?
It is used to move the cursor/insertion point to the previous screen.

 What is the Page Down key?
It is used to move the cursor/insertion point to the next screen.

What are keyboard  Arrow Keys?
The keyboarding arrow keys have arrows on them, and they move the cursor/insertion point up, down, left, and right. 

What is the Scroll Lock key?
It lets you use the arrow keys to scroll through a document rather than to move the insertion point/cursor through the document.