Most leaves are green in color because of chlorophyll which is a pigment responsible for photosynthesis that is the process of food production in plants, this makes the leaves green because most light waves are being absorbed except for the wavelength that is carrying or trasmitting  green that is reflected back.
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This is caused by the presence of a pigment called "chlorophyll," which the plant produces to do photosynthesis.

The chlorophyll is green because it absorbs red and blue wavelengths of light , thus, green is not absorbed and is reflected, making the plant look green to your eyes.