Which functions check if a post has featured image?

Which function should a plugin use in order to echo a string to the browser and make it translatable?

Sidebars should be added on the ____ hook.

What function do you use to register a new custom image size?

How can you write local files to the filesystem securely?

JavaScript strings should be translated by using?

If you need to save data in WordPress for a limited amount of time, what is the best way to do this?

Using bloginfo() without a parameter will default to?

Which step isn't a part of installing WordPress multisite?

Name of the function allowing you to register your own shortcode?

How can you enable WP multisite support in wp-config.php?