Importantance of a designer to draw an FMC Diagram

Why is it important for a designer to draw an FMC Diagram? (50-70 words)

Why is it important for a designer to draw a Use Case Diagram? (50-70 words)

Why is it important for a designer to draw an Inheritance Class Diagram? (50-70 words)

Why is it important for a designer to draw an Activity Diagram before building the system? (50-70 words)