what is true regarding slack? (choose all that are true) group of answer choices use of total slack prevents its use on a following activity. slack is the amount of time an activity can be delayed before it becomes critical. slack is the amount of time the activity can be delayed without affecting the early start of the activity immediately following it. free slack and total slack are essential and required for any project to finish on time since free slack can be delayed without delaying following activities, it gives some resource flexibility to the project manager slack usually occurs at the end of an activity chain—before a merge activity