What is the difference between real or physical evidence and testimonial evidence?

What is the difference between real or physical evidence and testimonial evidence?
Provide 5 examples of real or physical evidence that might require explanation in court by you because you are the one recording, recovering, processing, and packaging the evidence you recovered.
Why is real or physical evidence important for the triers of fact (jury)?
What is demonstrative evidence, and why is it used to clarify issues in trials?
What is the difference between direct evidence and circumstantial evidence? Explain.
What is the concept of overwhelming circumstantial evidence? Explain.
Can circumstantial evidence be enough for a conviction? Why or why not?