What goes up but never comes down?

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

Give it food and it will live; give it water and it will die.

Here is a mathematical expression that also secretly tells a movie name. What movie is that?

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?

Living above a star, I do not burn
Eleven friends and they do not turn
I can just be visited in a sequence, not once or repeatedly
PQRS are my initials
Can you tell my name accurately?

Find the missing number in the image below.

Open a Laptop which is password protected. Hint for the password is given as below:

1 mobile 3 books 2 Boards 1 night 4 balls 2 lighters 1 ghost 1 hat 3 watches

What has a ring but no finger?

There's a day, that comes around once a year.
To celebrate the man, you hold dear.
He gave you life, love and will pick you up if you fall.
When it comes to guys like him, He's the best of all.
Who is he?