This is because not all genes are expressed at the same time, so not all the proteins are present at a certain moment. The mechanisms that cell uses to control gene expression are called regulation of the gene expression. Thanks to regulation of the genes, cells have the ability to increase or decrease the production of specific gene products such as proteins. This property is important for the adaptability of an organism because it allows the cell to express protein when needed.
Oxygen molecules diffuse fast because the main gas in a cell in Carbon Dioxide its like if it was 99.9 percent carbon that .1 percent is oxygen and carbon dioxide being what it is. Automatically overrides the amount of oxygen. Basically it is nonpolar
Airborne is the most common.
Because the environment is faster then the squrrel has to find stuff for the nest and a safe spot
