Compare the three popular scheduling tools milestone chart, Gantt chart, and PERT/CPM network diagram

Compare the three popular scheduling tools milestone chart, Gantt chart, and PERT/CPM network diagram

Q1. Compare the three popular scheduling tools milestone chart, Gantt chart, and PERT/CPM network diagram. (from 250-to 300 Words)

Q2. Why is it so difficult to control technology-intensive activities and projects according to established plans? (from 250-to 300 Words)