Question: Why is the grass green?

Sebastian Gornik answered on 16 Nov 2016:

Grass is green, like every green plant because they have a special device – a so called organelle – in their cells called a chloroplast. This chloroplast is a remnant of a bacterium that millions of years ago existed and harvested sunlight. An ancestor of all modern plants including grass has taken up this bacterium and learned to life together with it. The two cells became one and share the workload, the bacterial part harvesting the sunlight and making energy and the other part providing shelter structure and a safe home. The light harvesting process in the chloroplast uses a colour pigment to collect energy from sunlight. We see these pigments as a green colour, hence all the plants appear green to us, including grass.