Fill in the blank: A(n) ______ is an observable change that can help project managers determine the overall health of a project.1 pointIssueMilestoneSignalRisk

To fill in the blank in the statement "A(n) ______ is an observable change that can help project managers determine the overall health of a project," the most appropriate answer is "Milestone."

Explanation:

1. Milestone: In project management, a milestone signifies an important point or event in the project timeline. It indicates progress and can help in assessing whether the project is on track.
2. Issue: While an issue is a problem that arises, it does not inherently provide insight into project health without context.
3. Signal: This term is vague in this context and is not specifically a project management term for measuring health.
4. Risk: Refers to potential problems but doesn't indicate observable changes in project progression.

Thus, the complete sentence would read: "A(n) Milestone is an observable change that can help project managers determine the overall health of a project."