What makes plants so green?

Answer 1

Chlorophyll. Chlorophyll is the plant version of mammal Hemoglobin, Chlorophyll is green while Hemoglobin is red. Both chemicals are necessary for energy metabolism in their respective plants and animals, with Hemoglobin animals consume Oxygen and exude Carbon Dioxide, and with Chlorophyll plants use the energy from the Sun to consume Carbon Dioxide and exude Oxygen.

Both chemicals and their use/production require the mineral Iron. Fertilizers with high Iron content are a great way to make plants green to a surreal level. Correspondingly, Iron rich diets in mammals cause an increase in Red Blood Cell production. Too much, like any metallic element, is harmful.

There has been speculation on the possible importance of ORME metals in this process.