Question

barrier islands are areas of sand that are formed from the wave and tidal action that occurs parallel to the coastline. a scientist kept track of the changes to the shoreline of a barrier island over a period of time.
which best explains why the shoreline of the barrier island has changed since 1851?
a. after years of absorbing the impact from destructive forces like hurricanes, the sand of the barrier island slowly eroded causing the shoreline to become more narrow.
b. after years of movement from wind, constructive forces, such as deposition, occurred on the barrier island creating sand dunes and causing the shoreline to shorten.
c. after years of repetitive movement from the waves, a constructive force, such as deposition, occurred causing the sand to create a sandbar in the ocean and the shoreline to be shortened.
d. after years of high winds during destructive forces like hurricanes, the sand from the shoreline eroded from the bottom causing the shoreline to shorten which also created a higher elevation for the shoreline.

Explanation:

To determine the best explanation, we analyze each option:

• Option A: Erosion from hurricanes (destructive) would likely remove sand, but the explanation of "sand ending" is unclear and not a standard geological term. Also, narrowing the shoreline due to absorption is not accurate.
• Option B: Wind movement causing deposition (constructive) to form sand dunes. However, sand dunes on a barrier island are more related to wave action than wind for shoreline change.
• Option C: Waves (repetitive movement) cause deposition (constructive force), which can create a sandbar in the ocean. This deposition would move sand from the shoreline area to the sandbar, shortening the shoreline. This aligns with how barrier islands and shorelines change due to wave - driven deposition.
• Option D: Erosion from the bottom due to hurricanes (destructive) and creating a higher elevation is not a typical or well - explained process for barrier island shoreline change.

So, Option C provides the most accurate explanation as wave action (repetitive movement) leading to deposition (constructive) and sandbar formation, which shortens the shoreline.

Answer:

C. After years of repetitive movement from the waves, a constructive force, such as deposition, occurred causing the sand to create a sandbar in the ocean and the shoreline to be shortened.