Forwards I am heavy, backward I am not. What am I?

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?

Solve the riddle below:

If a Chicken says, 'All chickens are liars" is the chicken telling the truth?

Look at me. I can bring a smile to your face, A tear to your eye, Or even a thought to your mind. But, I can't be seen. What am I?

Find the smallest sentence with all the English alphabet.

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

A woman who works in a sweet shop has a measurement of 32-26-36, is 5"4" tall, and wears size "6" shoes. What do you think she weighs?

If 24H in a D => 24 hours in a day.
What does "64S on CB" stand for?

What country can make you shiver?

Why did Navjot Singh Sidhu put the new January calendar in the freezer