A scientist is trying to find how changing the thickness of a paper towel affects the volume of water that it will hold.

What things should be held
constant?

altitude, density, pressure

air gets less dense the higher the altitude and also the air pressure is less as altitude rises.

frequency, z, and the collision density, z, in carbon dioxide (co2), r 180 pm at 30 °c and 120 kpa

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.