A.
Physical change
Step by step explanation;:)
When a gas bubbles through water, small droplets of water are usually picked up along for the ride and are mixed in with the gas above the water inside the eudiometer tube. The water vapor takes up room, but isn't the important gas that you need to measure. The table of water vapor is needed to subtract the unwanted water vapor from the collection of gases.
I believe the answer is D
All the elements in one group have the same number of valence electrons.
