From the research that I have done, exports to the United States increases the country's balance of trade. Possibly creating a surplus of goods.
The correct answer would be an increase in exports to the United States
Here is a good example of what you are trying to understand.
<span>If a country exports a greater value than it imports, it has a </span>trade surplus<span>, </span>positive balance<span>, or a "favorable balance", and conversely, if a country imports a greater value than it exports, it has a </span>trade deficit<span>, </span>negative balance<span>, "unfavorable balance", or, informally, a "trade gap". A positive balance adds to </span>gross domestic product<span>, while a negative balance subtracts from GDP.</span>
The variable is the group that was given caffine, because thats what the doctors manipulated. They possibly altered the natural memory of the participants by giving them caffine. A more specific variable could be how much caffine each participant is given and what time are they given it.
Answer:
I don't know but you blink the light when switching roads so you must blink and then change the lane hope that helps