Question

1. read the following paragraph from the introduction paragraphs 1 - 5. some water companies are streamlining their treatment process even more by installing technologies such as reverse osmosis. this technique removes nearly every contaminant in water by forcing the water molecules through a selectively permeable membrane — one with really tiny holes. reverse osmosis can replace a number of steps in the water treatment process or reduce the number of chemicals added to water. but its expensive — out of reach for many cities. what conclusion is best supported by the paragraph above? (a) reverse osmosis is the safest water treatment system and it is the most economical. (b) reverse osmosis is the least reliable water system and it is the one that is the most expensive. (c) reverse osmosis is more efficient than other water treatments, but it is often unaffordable. (d) reverse osmosis is the slowest water treatment system, but it is also the least costly

Explanation:

The paragraph states reverse - osmosis removes nearly every contaminant, can replace steps or reduce chemicals (showing efficiency), but is expensive and out of reach for many cities.

Answer:

C. Reverse osmosis is more efficient than other water treatments, but it is often unaffordable.