There is more variability in test tubes than with calculations on paper, more variability with cells than test tubes, more variability with rats than cells and more variability with humans than rats. Weight is a force. Force varies with gravity. You weigh more on land than you do in a swimming pool. You would weigh less on the moon, if you had the opportunity to go to the moon.
Liquids change shape according to the container, but have constant volumes.
Gases change shape and volume, it expands to fill its container. D. Pure substances 1. 24 O 11 E. Mixtures 1.