What is a "PEE" chain?

You begin with the "P" which is "Point" and here you make a statement. For example, "Cats are the best household pets for young families". 

Then, the first "E" is evidence. Here is where you state the facts which support your statment. For example, in the same case, you could use "They don't need regular walks". 

The final "E" is explain. Here you explain why the fact or evidence you have provided supports your assertion (Point). With the same point, you could say "This means they are low maintenance therefore the parents don't need to worry too much about the cat and can keep their children as a priority". 

To make your answer a higher level response, you can add "L" to the end of the PEE chain which is "Link". Here you link your whole paragraph (The Point, Evidence and Explanation) to the original essay question. So with the mini and very simple paragraph we have created, the question could have been "Cats make the best all-round pets. Discuss".