Explanation:
Students about to take an exam would likely be experiencing higher than normal anxiety
Answer: stimulus
The students reaction is explained by the theory of classical conditioning first coined by Ivan Pavlov. The students are conditioned to associate the doer closing with the pop quiz and respond accordingly. Pavlov used dogs and their response to ringing a bell every time their food was served, after a some conditioning the dogs would salivate at the sound of the bell regardless of whether or not food was present. The bell was the stimulus.
Make do with what you have. The Mesopotamians gave us a very valuable building material the brick. Having no locally available stone they used the plentiful supplies of mud and clay found on the banks of the Euphrates to make bricks.
There is also trade, exchange what you have for what you lack. In their case it was agricultural produce. This is how Babylon became a thriving and powerful city.
Finally when you finally become more powerful take the resources from your neighbours by force.