Differences between due to and because of

I always thought that due to and because of are interchangable. Today I found that there is a lot of differences in their usage. I will be quite thankful if anyone could elucidate it for me.

Crazy English

Can you play the guitar?
Can you play tennis?

Could anyone explain why we use define article before the guitar and why we don't use article before tennis?

The with the cardinal number or without it

The first three words or first three words?

I hadn't any doubtsif it would be only the first word and not the first three words

Buy something at or in

Buy сologne at or in perfumer's

Buy goldfish at or in pet shop

Buy drug at or in pharmacist

How Americans call the store where we can buy only glasses?

Optician's as a guess is British name

What is the difference between title and headline

It's quite confusing

Georgia Georgia is an ancient country between Europe and Asia. Those who once visited it, try to arrived here again and again. Landscape of this small is quite attractive. Mountainous areas interchanges with plains. It's really awesome that only several hours drive separate high snow flops from flourishing valleys. Georgians are famous for their hospitality. They believe that every guest sent by Lord/ That's why they wine and dine everyone? who knocks at the door. Visit Georgia and you will be convinced that it's worth to come back again and again.

Is there any difference between error and mistakes 12 common mistakes of English learners or 12 common errors of English learners

The doctor gave me a receipt/prescription for drugs which id right?