They change shape due to a number of reasons.
The easiest reason to understand why they change is that they erode.
The coasts around the the world erode due to waves hitting cliffs, the wind batting against the coasts etc. Over a long period of time we can see that they change in shape.
(sorry I don't know why they move)
Answer:
Dangle
Explanation:
Droop, hold, and to suspend someones feet into a pool are all words that sound awkward. Dangle is the most sensible answer.
I think reads should choose texts with dynamic characters that they find interesting.
Possible answer: Sentence 4