It would be useful for a story I'm working on to color the world or various dominant parts of it red. I'm trying to look into the following alternatives, but am open to further suggestions. Essentially I'd like to know what gives some things their color and how this could be plausibly explained to be red on another planet.
1) grass and vegetation: as far as I understand, plants are green in order to absorb a particular wavelength of light, but it is unclear to me why that one color in particular. Is it feasible that a different type of sun would give rise to red plants?
2) water generally: both rivers and the ocean; to us it appears blue, but could it appear red and how/why?
3) the clouds. What makes them white and can they be red on another planet?
Finally, I'll probably settle on just one such element, but I'm curious as to whether all could be coherently part of the same world.
Following on the great answers provided I want to further clarify the following:
Would humans living there/having evolved there see things other than red, and humans coming from Earth perceive more of the red? Would the skin of indigenous people be/appear red to visitors? (And not vice versa). Could it be that foreign humans see things reddish, while indigenous humans see them... how? Normal?