[null and void]

I usually refer to it in conversation as "the essential plant nutrient, CO₂..."

[exDemMom]

I usually refer to it in conversation as "the essential plant nutrient, CO2..."

Actually, it is the building block of all life, since every carbon molecule in our bodies originated as CO2, processed into usable form by plants. (But I think you know that.)

Recently, at a career fair at a local elementary school, I showed kids a CO2 molecule and told them that it is carbon dioxide, which plants eat. I didn't say a thing about the global warming nonsense.