What is oblique symmetry?

Yes.

There are three elements of symmetry: 1-axis of symmetry It's a line which cuts the molecule into two equal halves. 2-plane of symmetry It's a plane which cuts the molecule into two equal halves...

Yes.

parallelogram* * * * *A parallelogram does have rotational symmetry (order 2).

Line symmetry is like with butterflies or flowers, where you can slice a straight line through the midpoint of a shape, and have both sides be identical. Reflectional symmetry is where lets say to...