Examlex
The minimum size of a meteoroid that is capable of surviving its passage through Earth's atmosphere and hitting the ground is about as big as:
Barter
The direct exchange of one product for another without using money.
Medium Of Exchange
Anything that is widely accepted as a means for the payment of goods and services and repayment of debts.
Opportunity Cost
Represents the value of the best alternative that must be given up in order to pursue a certain action or decision.
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