21. Check-in, Incident Action Planning, Personal Responsibility, and Resource Tracking are all necessary to ensure:

Accountability

Explanation:

The term accountability denotes the ability of a person to be responsible for one's actions. However, the word in the context of a business, it also consists of all the steps that people at different levels have to obey and follow in order to allow for effective utilization of resources of the business.

"Check in" means reporting in person to receive or assign a certain task to perform.

"Incident Action Planning" to coordinate among different activities.

"Personal Responsibility" is when each and every person is responsible for his deeds and action in any activities.

"Resource Tracking" means hunting down and recording the changes in resource status and reporting it.

Thus the answer is Accountability.