Why did the experiment put antacid tablets into one of the bottles

The tablet pulled greenhouse gases from the air, cleaning the air in the bottle

The tablet formed carbon dioxide, which will act as the greenhouse gas in its bottle

The tablet made fizz in the sound of popping bubbles was measured

The tablet colored the water, which caused it to be easier to see

The tablet put into the bottle because it will form carbon dioxide which will act as the greenhouse gas in that bottle.