Two-dimensional (2D) shapes are completely flat. They cannot be picked up. 2D shapes can be found printed in a book or you can draw them on a piece of paper. 2D shapes have sides and corners (also ...

Tiny channels of nanometer scale (1 nanometer = 1/billionth of a meter) are found in nature that allow substances to pass through and filter out impurities. These are present in human cell linings and ...