Is it possible to use or add a fragment without using a user interface? 

Comments are Non Executable statements in program & Explain program logic.

Social engineering is the art of tricking users into performing certain harmful activities or attacks, users must be trained to identify social engineering. Social engineering attacks typically involve some form of psychological manipulation, fooling otherwise unsuspecting users or employees into handing over confidential or sensitive data. Commonly, social engineering involves email or other communication that invokes urgency, fear, or similar emotions in the victim, leading the victim to promptly reveal sensitive information, click a malicious link, or open a malicious file. Because social engineering involves a human element, preventing these attacks can be tricky for enterprises.

The input type attribute TYPE defines the slider control.

PHP is similar to the C style syntax in terms of keywords and language syntax.

If conditions, for and while loops, and function returns are similar in syntax to languages such as C, C++, C#, Java and Perl.

APK stands for Android Application Package.

Android Package (APK) is the package file format used by the Android operating system for distribution and installation of mobile apps and middleware.

A Records Management System is a computer program or set of programs used to manage and store records.

For example, a hospital record for storing new room, ward , patients, etc...

A website main page is called as start page or home page.

True, the given statement that xml preserves white spaces is correct.