Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

In a concert, Christina is performing a dance show with her group.
At 10:00, she and her crew were dancing in an absolutely straight line. At that time Christina was standing in 4th position from both the front and back end of the row.

What was the size of her crew?

I am 5 letters long.
My first two tell you who I am
My first 3 could be a medicine
My last three reversed could be a young boy.
My 4th, 3rd and 2nd in that order could be a fruit drink.
If you have me you may hang me round your neck
WHAT AM I ?

I am sure no one can have two things for dinner. what are they?

O_er_t_o_

Complete the missing letters of the given word.

By what process could you make a 'Tea-Table' into food?

What have one eye but still cannot see?

How many points are there on the globe where, by walking one mile south, then one mile east and then one mile north, you would reach the place where you started?

How many bricks does it take to complete a building that is 15 feet wide, 30 feet deep, and 12 feet tall made of brick?

They came out at night, without being called.
They lost at day, without being stolen.
Who are they?