When particles are suspended in liquid (like pollen in a water glass),they will zigzag randomly through the liquid and collide with one another in perpetuity. This type of random, continuous __ is known as Brownian motion, can be observed throughout the natural world. Which choice completes the text so that it conforms to the conventions of Standard English? A. movement: which B. movement, which C. movement which D. movement. Which

## Step 1<br />The sentence is discussing a type of motion known as Brownian motion. The sentence is divided into two parts: the first part introduces the concept of Brownian motion, and the second part provides additional information about it. <br /><br />## Step 2<br />The second part of the sentence is providing additional information about Brownian motion, which is a non-restrictive clause. Non-restrictive clauses provide additional information about the noun they modify, but this information is not essential to the meaning of the sentence.<br /><br />## Step 3<br />In English grammar, non-restrictive clauses are usually set off by commas. Therefore, the correct choice is B. "movement, which". This choice correctly uses a comma to separate-re clause from the rest of the sentence.