What do you answer even though it never asks you questions?

Spot 5 differences in two Christmas tree below:

What is the relationship between these matchstick pictures below?

We know that money can be names differently for the purpose it is used for. Some of the examples of money given at following places or for following activities:

In temple = Daan
In school = Fees
During marriage = Dowry
For divorce = Alimony
Paying government = Tax
In court = Fine
Employer to employee = Salary
To kidnappers = Ransom
For illegal reason = Bribe
To civil servant retirees = Pension

Do you know what do we call the money a husband gives to his wife?

I taste better than I can smell. Who am I?

John decided to give his bike 3 coats of paint. Which coat would go on the first?

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

Replace the question mark with the correct number.

What's a single-digit number with no value?

There was once a college that offered a class on probability applied to the real world. The class was relatively easy, but there was a catch. There were no homework assignments or tests, but there was a final exam that would have only one question on it. When everyone received the test paper it was a blank sheet of paper with a solitary question on it: 'What is the risk?'.Most students were able to pass, but only one student received 100% for the class! Even stranger was that he only wrote down one word!
What did he write?