What is cockney rhyming slang?

Hi guys! I assume you've all got the text we're going to work with. In case you don't, you can get it HERE.

Ok, now, read it carefully and answer the following questions afterwards:

a) Originally, what part of London did Cockneys live?
b) What is the original meaning of the word cockney?
c) What does the rhyming slang cosnsit of?
d) Why did the rhyming phrases often lose the second (or rhyming) part?
e) Is cockney rhyming still used nowadays? What is the trend today?

Now, have a look at the examples in the text and try to provide a translation into standard English as follows:

I can't open the door! I'm talking on the dog!!! >> I'm talking on the phone (dog and bone = phone)

a) I need to buy a new pair of one's for the party.
b) Turn the custard off and let's get to work!
c) Use your loaf to work out the problem.
d) She is the twist I like.
e) If we don't get home on time we'll get into big barney!
f) The kids are in the bedroom: just go up the apples over there