red jigsaw puzzle

Red is the colour at the end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–740 nanometres. It is a primary colour in the RGB colour model and the CMYK colour model, and is the complementary colour of cyan. Reds range from the brilliant yellow-tinged scarlet and vermillion to bluish-red crimson, and vary in shade from the pale red pink to the dark red burgundy. The red sky at sunset results from Rayleigh scattering, while the red colour of the Grand Canyon and other geological features is caused by hematite or red ochre, both forms of iron oxide. Iron oxide also gives the red colour to the planet Mars. The red colour of blood comes from the protein hemoglobin, while ripe strawberries, red apples and reddish autumn leaves are coloured by anthocyanins.