Because its air we cant see it thats why its clear because it would be scary if we were able to see air! :)
The study of population is useful because you can see how popular sections of your country or even the world are. You can see where the most dense parts of Cities and countries are to see what kinds of regulations you might have to put in place for say, worldwide pandemics such as the Coco-19 pandemic. It's also useful because you can see why certain area are more popular than others. reaons might include things like mining towns drawing in people from around that area etc etc. The study of population might also be useful if you're trying to establish a busniess and want to start it in a place you know it'ss be successful, such as a higher populated town near you.
The study of population can also be refered t as population demographics or demography.
Answer:
(40 °F - 140 °F)
Explanation:
The danger zone is in between (40 °F - 140 °F), food should not be left out for long
