line or shape?

1) Which of the images a,b,c,d are lines?
All of the images are lines, because lines can be open where they don't meet, or closed where they connect together.

2) Which of the images a,b,c,d are shapes?
All of the images are shapes because they all have a form to them. They are just a flat.

3) What makes a line?
A line can be open where it never meets or ends, or closed, where the lines connect together.

4) What makes a shape?
A shape can be 1-D, 2-d, or 3-D. It has to have an area, and a perimeter. 2-D shapes have volumes and masses. A shape is anything with a closed form.