What occurs twice in a week, once in a year but never in a day?

In a jungle where there are no street lights or any other artificial source of lights, I notice a black snake crossing the road.
How did I get sight of the snake?

There are three boxes of different sizes with three cupcakes inside each of the boxes in Christina's kitchen. At night her daughter wakes up and goes to the kitchen. She opens a box and eats all three cakes.

But in the morning Christina finds out that each box still had three cupcakes. How?

You have to put a letter on the following to make it a meaningful word. The only challenge is that you can't use 'E'.

S E Q U E N C _

What is the longest word in the dictionary?

A container contains 100 eggs. They can be either fresh or rotten. What is sure is the fact that there is at least one fresh egg in that container.

If you are asked to pick two eggs randomly from the container, at least one of them will be rotten.

Can you calculate how many eggs in that container are fresh?

No one wants to have it, but if one got it, he does not want to lose it. What is It?

Irene killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

A bomb goes off.
Carnage.
One person, only a few feet away, survives! How can this be?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?