"Some Simple Water Science" differs from "Water For The World" because the passage describes the desalination process, while the other one discusses how desalination can help solve the water crisis.
"Water For The World" says that water is important because it is needed for survival, and it is also needed to grow plants and crops. Both sources touch on how fresh water is becoming more and more limited for the growing population.
Explanation: for example when you are quoting someone or a source you can use elipsis to skip not relevant part. However it is crucial to preserve meaning of original sentence and not manipulate it with elipsis like some media do.
