A. The pressure is lower as you gain altitude because there are more molecules of oxygen and nitrogen. B. The pressure is lower as you gain altitude because there are less molecules of oxygen and nitrogen. C. The pressure is the same because there is no change in the number of molecules.
The price of a cockatiel depends on a few factors. Firstly the price depends on whether or not the bird is tamed. For a tamed cockatiel it would cost around $80 - $120 and a untamed cockatiel would cost $15-$30 (AUS) Also the colouring of the cockatiel plays a part in the cost of the bird, as more rare colours (such as lutino or pearl cinnamon) may increase the cost of the cockatiel.
It is also called as Wiero and Quarrion. Cockatiels have the capacity to breed easily and are a famous household pet worldwide. In captivity, they come next to the very popular Budgerigar. Generally, cockatiel life span reaches 20 years or so though the standard is 15 years. Furthermore, some reports say that there were cockatiels which lived for three decades and more and you should be lucky if the one that you got reached or comes close to this age.