How has the biosphere changed overtime?

Over a long period of time, the atmosphere developed a mix of oxygen and other gases that could sustain new forms of life. The addition of oxygen to the biosphere allowed more complex life-forms to evolve. This exchange of food and energy makes the biosphere a self-supporting and self-regulating system.

Explanation:

biosphere changes little from year to year, but there are small variations. Plants require four things to grow: nutrients, light, water, and moderate temperatures

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Explanation:

i think the answer is a.keratin is the pigment responsible for skin color.