What number when divided in half becomes zero?

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?

Find the number of squares in the below-given picture.

I am a type of room you cannot enter or leave. Raised from the ground below, I could be poisonous or a delicious treat. What am I?

Before Mount Everest was discovered, what was the highest mountain in the world?

You are an expert on paranormal activity and have been hired to locate a spirit haunting an old resort hotel. Strong signs indicate that the spirit lies behind one of four doors. The inscriptions on each door read as follows:

Door A: It's behind B or C
Door B: Its behind A or D
Door C: It's in here
Door D: It's not in here

Your psychic powers have told you three of the inscriptions are false, and one is true. Behind which door will you find the spirit?

Replace the question mark with the number below given a simple math problem.

What do the following words have in common?

Assess
Banana
Dresser
Grammar
Potato
Revive
Uneven
Voodoo

I cannot talk, but I always reply when spoken to. What am I?

What does this mean?

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