Which country gets ill every time?

How many words can a quill made with the feather of a pigeon write with a 100ml bottle of black ink?

John is looking at Jenifer, but Jenifer is looking at Jacob. John is married, but Jacob is not.

Is a married person looking at an unmarried person ?

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

On a certain day, John celebrated his birthday. Two days later, his older twin brother Jacob celebrated his birthday.

Is this even possible? How can it be?

They are three errirs in this question. Can you find them?

If all Goats are Sheep and all Sheep are Deers, are all Deers Goats ?

What breaks yet never falls, and what falls yet never breaks?

What number does the below three word/phrase identify and why?
1. Deck
2. Year
3. Singing in the Rain

I can be made.
I can be cracked.
I can be told.
I can be played.

Who am I?