Why are leaves green?

The green color in leaves is caused by the presence of a compound called "chlorophyll," which the plant produces to do photosynthesis, which is how plants get energy from sunlight. The purpose of chlorophyll is to assist the plant in making food for itself by utilizing energy from sunlight and nutrients from the soil.

The chlorophyll is green because it absorbs red and blue wavelengths of light -- and so green is not absorbed and is reflected, making the plant look green to your eyes. Non-transparent things are the color they are because that is the color that is NOT absorbed -- the color you see is the color that is reflected... which is why you see it!

Why are most plants green?

Most plants appear green because they contain chlorophyll, a pigment within the leaf and stem structure that reflects the wavelengths of light that make up the color green. Chlorophyll absorbs other wavelengths of light and uses the energy to produce nutrients.

Why is my poop green?

Healthy people can have green poop if they eat a diet rich in leafy green vegetables, or if they consume large quantities of food coloring (in ice cream, cake frosting etc.).

Green poop can also be caused by excess iron in the diet, from dietary supplements, for example. If the body does not absorb all the iron consumed, the iron may stain the poop green, the color of iron (II) salts. Ordinarily, the green color may be masked by the normal brown poop color, but if digestion is thrown off by illness so that bilirubin is less concentrated in the intestine, the green color may become apparent. This can happen when a person is afflicted with diarrhea.

Green poop in sick babies may come from iron in baby formula not being properly absorbed, or by green pigments in bile salts (again, green from iron).