Question 4
Why is the coloured water drawn up the tube in setup A of activity 03?
The right answer is the one marked above.
Because the seeds absorb oxygen while the CO2 they release dissolves in the KOH, so the volume in the flask falls. Gas leaves and nothing is added back, and water is drawn in behind it to fill the space.
If heat expanded the gas, the water would be pushed down rather than drawn up. The KOH attracting water is not the point here; it sits in the test tube, not in the water vessel.