Modules

Advance Workflow Management will help workflow admin define single workflow with states adding a layer of groups at top of that; access control will be based on groups. This module will create a new tab "Workflow Groups" through which admins can create various roles as workflow groups, assign group role to the user (author/editor/publishers) along with the role that manipulate workflow.

Drupal API provide a hook function hook_block that allow developers to create block or set of blocks their way. hook is a keyword that will replace by the module name, for example example.module file will implement this hook as example_block()

For further details about this hook please visit here

Drupal APIs and Drupal framework allows developer to provide means for other modules to interact or intervene using hooks. This can be done by simply using an API called module_invoke_all(), a comprehensive detail for this function can be found here. Details about hooks in drupal can be found here