In this case, according to the given information, it is possible for us to approach this problem via the ideal gas law, which involves the pressure, moles, temperature and volume of the gas:
Thus, by solving for moles we obtain:
Therefore, we plug in the given volume, temperature (in Kelvins) and pressure to obtain:
An animals life in a desert is to survive, depending on the type of desert though, but I assume the most common desert, the hot/dry desert. Most animals are nocturnal, because it becomes cooler at night, and live underground during the day.