Why might Rubisco have evolved with an inability to distinguish between CO₂ and O₂? A)low atmospheric O₂ levels when Rubisco evolved B)low atmospheric CO₂ levels when Rubisco evolved C)high atmospheric O₂ levels when Rubisco evolved D)multiple subunits in the Rubisco enzyme competing for substrate E)selective advantages for plants that are able to bind both CO₂ and O₂

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Rubisco evolved at a time when the atmospheric levels of O2 (oxygen) were much lower and CO2 (carbon dioxide) levels were higher than they are today. This meant there was less need for the enzyme to distinguish between CO2 and O2, leading to its current form which can inefficiently bind to both.

Why Might Rubisco Have Evolved with an Inability to Distinguish