Answer:
1. Air warms, becomes less dense, it rises
2. Air cools down, increases density (becomes denser), it sinks
Building models doesn't actually help scientists observe phenomena. Scientists build models to describe how nature and systems operate then make observations to see if their models match what they observe. Models which don't match what they observe are either alterated or scrapped. Good models are kept and used by the scientific community.
They are called Polygenic Traits and height is an example.
B. Being new to the country, it is safer for Sarah to take precautions until she gets acclimated
I believe this is the answer as the other answers take too many assumptions as the question doesn't explicitely state that Sarah has skin problems.
Answer:
colds are cause by viruses
