Yes Carbon dioxide is necessary for photosynthesis because Photosynthesis didn't go on because there was no Carbon dioxide in flask X.
The carbon dioxide was absorbed by the sodium hydroxide. In flask Y, the colour of the iodine solution turned blue black. This is because starch was present in the leaf of flask Y. Starch was present because it underwent photosynthesis.
Liver contains a enzyme called catalase. When hydrogen peroxide (H2O2) is added to liver, a chemical reaction occurs which results in the production of oxygen gas (O2) and liquid water (H2O).
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Increase and decrease in oestrogen and progesterone.
I believe it is Nitrogen dioxide
