Lung cancer is the top cause of cancer deaths in both men and women. But this wasn't always the case. Prior to the widespread use of mechanical cigarette rollers, lung cancer was rare. Today, smoking causes nearly 9 out of 10 lung cancer deaths, while radon gas, pollution, and other things play a smaller role.
From Wikipedia, the free encyclopedia. A plane symmetry is a symmetry of a pattern in the Euclidean plane: that is, a transformation of the plane that carries any directioned lines to lines and preserves many different distances. If one has a pattern in the plane, the set of plane symmetries that preserve the pattern forms a group. The groups that arise in this way are plane symmetry groups and are of considerable mathematical interest. A symmetry plane is a three-dimensional object's symmetry axe. There are several kinds of plane symmetry groups: Reflection groups.
Reflection symmetry, line symmetry, mirror symmetry, mirror-image symmetry, or bilateral symmetry is symmetry with respect to reflection.That is, a figure which does not change upon undergoing a reflection has reflectional symmetry. In 2D there is a line of symmetry, in 3D a plane of symmetry.nother way to think about the symmetric function is that if the shape were to be folded in half over the axis, the two halves would be identical: the two halves are each other's mirror images. Thus a square has four axes of symmetry, because there are four different ways to fold it and have the edges all match.