Explain the check points in QTP?

A checkpoint verifies that expected information is displayed in a Application while the test is running. You can add eight types of checkpoints to your test for standard web objects using QTP.
 A page checkpoint checks the characteristics of a Application
 A text checkpoint checks that a text string is displayed in the appropriate place on a Application.
 An object checkpoint (Standard) checks the values of an object on a Application.
 An image checkpoint checks the values of an image on a Application.
 A table checkpoint checks information within a table on a Application
 An Accessibility checkpoint checks the web page for Section 508 compliance.
 An XML checkpoint checks the contents of individual XML data files or XML documents that are part of your Web application.
 A database checkpoint checks the contents of databases accessed by your web site