Closed and Open Figures

Q.

can a simple curve be closed ?

Q. Define the terms:
(i) Open curve
(ii) Closed curve
(iii) Simple closed curve

Q.

I take a round glass tumbler and trace its outline onto a paper sheet. What type of curve is it?

Q. What is a simple curve and simple closed curve ?

Q.

Consider the given figure and answer the questions:

(a) Is it a curve? (b) Is it closed?