None or one.
four lines
Contour-line drawing refers to drawing the outline of something,usually a human figure. Matisse has many examples of this.
That will depend on the shape of the figure which isn't named
There are many ways to create a stick figure using standard textual symbols. 'o-[-
If the figure is an image of a real heart, then there are no lines of symmetry. If it is an idealised heart, then 1.
It depends on the irregular figure. A rectangle, for example, has two.
An octagon is an eight-sided figure.
A lot
It can certainly have 0, 1, 2 or 6 lines of symmetry.
Go on poptropica and figure out yourself!!
Anything from none to 8.