Explain Reliability testing ,usability testing and Security testing ?

Answer:

Reliability Testing :It is a type of testing in which one will use the application continuously for long period of time inorder to check the stability of the application
Usability Testing :It is a type of testing in which one will check the user friendliness of the application.Generally during this testing they will check the following messages, font, color .etc
Security Testing :It is type of testing in which one will check when the application is properly protected are not.Generally this is done by black box test engineers.