The slot covers on a computer reduce the dust build up inside the computer. So the slot covers should be present in proper place.The missing covers can disrupt the airflow design of the case and cause overheating problems.
Woodrow Wilson was referring to the liberal idea of the economic market when he said that the free enterprise system is the (much) efficient economic system.
Adam Smith propounded the following first four canons of taxation -(1)Canon of Equity. (2) Canon of Certainty: (3) Canon of Convenience or Ease (4) Canon of Economy.