8. Give a possible explanation for why some shoes drifted northward along the coast while others drifted southward.

The correct answer to this open question is the following.

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A possible explanation for why some shoes drifted northward along the coast while others drifted southward is because the ocean currents are different and can easily make an object to change direction, depending on the currents. Heavy storms can also be a factor in the changing of the current and the objects.

That is what happens with the May 1990 incident with a cargo ship from Korea that was sailing to Alaska, United States.  A heavy storm made 21 containers fall to the sea and 5 of them broke, releasing approximately 60,000 tennis shoes.  

Although the incident was close to the shores of South Alaska, it took them almost nine months to get to the shores of Oregon, and Washington.

The oceanic currents affected the direction of the tennis shoes.

this statement is true.

forests are public goods, available for everybody. when usage of such a good becomes interesting for consumers and its usage increases, there can be a risk of overexploitation. it is a non rival good therefore, if one person consumes the good it does not reduce the availability for subsequent consumers.

these caracteristics require the establishment of measures in order to prevent the destruction of a commonly owned space, for example, to restrict the amount of people that have access to the same time.