Marginal benefit" is most related to what economic concept?
a) opportunity cost
b) supply elasticity
c) demand elasticity
d) equilibrium price

A) opportunity cost

Explanation:

Opportunity cost refers to the value of next option available which is forgone in order to choose the current option. As the benefit is more in current option then the option forgone, the marginal benefit is basically the difference between the two options.

As for example if you earn $10,000 in current job and the opportunity cost is $8,000, then the marginal benefit is $2,000.

because if current job was not chosen then it would have earned $8,000, but the additional amount earned = $2,000.

this null effect is caused by a weak manipulation and ineffective internal validity. in a scientific study, as the one dr. morimoto is trying to perfom, internal validity refers to the confidence placed in the cause-effect relationship and to how well an experiment is done and able to eliminate confounding variables.        

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