Question

Why plants will take only
carbondioxide?

Answer 1

in the presence of water,plants can convert co2 into sugar and oxygen, basically starch ,which it cant get it in other gases

Answer 2

Plants need Carbon Dioxide to be able to conduct the Calvin Cycle. This is the part of photosynthesis that makes the sugars that plants need to carry out cellular processes.

To keep things short, basically what a plant does is take the carbon dioxide, and does a few chemical reactions with it to turn it into a molecule containing 12 carbon molecule. Part of this 12-carbon molecule breaks off to make sugar, and the remaining part goes back into the cycle so it can react with the next carbon molecule, and the cycle continues.

Carbon Dioxide in -> Reactions -> 12-carbon molecule -> part goes to make sugar -> other part goes back into cycle -> another Carbon dioxide in -> cycle restarts.

So basically without carbon dioxide Calvin cycle cant be performed and therefore no sugar/energy will be produced.Hence its necessary.