In the series X, Y, ?, Z, what character is missing?

A. W

Bird is to Nest as Fish is to ?

B. AQUARIUM

Identify the missing character in the series 1, 2, 4, 8, ?, 32.

A. 16

What character should replace the question mark in the pattern X, Y, ?, Z?

A. W

If the pattern is 1, 2, 4, 8, ?, 32, what number should replace the question mark?

A. 16