What are the three key characteristics about projects known as the triple constraint?

What are the three key characteristics about projects known as the triple constraint?
This will require the use of Microsoft Project in order to update the attached Gantt Chart.
The project charter and RACI chart have been approved by the Regatta University administration. Using the project Gantt chart, your team has started working on the project schedule based on these documents. The team needs to make sure that each member understands his or her responsibilities based on the schedule. This should be submitted as a Word document with double spacing, one-inch margins, 12-point Times New Roman font, and adherence to the latest edition of APA formatting. Also submit your updated Microsoft Project file.