For the environmental risk, it is much better to prevent pollution than to deal with it after it has already been made. When you deal with the pollution, it is hard to say that you can eliminate completely. So, prevention is the first strategy.
Yeast is very similar to human cells in that we have the same cellular respiration process. The formula for cellular respiration is C6H12O6(Glucose) + O2(Oxygen) = CO2(Carbon dioxide) + H2O
Because of this we know that the yeast is going to take oxygen from the air and the glucose in the test tube and produce carbon dioxide with it, so the full answer would be “The composition of the air in the test tube would change so that there is a higher composition of CO2.” If you need to explain it more pull from my explanation :)
brain or nervous system cells are called as neurons
The nitrogen in the air cannot be used by producers and consumers. It must be fixed or converted by bacteria in the ground into a useable form for plants called nitrates. Some plants called legumes (beans and clover) actually have bacteria in their roots.