Your question is rather unclear but from what I can tell either there were not an even amount of Petri dishes or some of them were left open while others were not.
The Great Plains have a continental climate. Much of the plains experience cold winters and warm summers, with low precipitation and humidity, much wind, and sudden changes in temperature. More rainfall occurs in summer than in winter, except in some of the northwestern parts of the Great Plains.
Hopes this helps!
The mouth is the beginning of the digestion tract , our mouth also produces enzymes to begin the process of digestion
