Which of the below owl is odd one out?

Only one color, but not one size,
Stuck at the bottom, yet easily flies.
Present in sun, but not in rain,
Doing no harm, and feeling no pain.
What is it?

Can you place six X (crosses) in below board without making three in a row in any way ?

Until it is measured, not known. Yet how you miss it when it has gone. What is it?

Can you find the key in the picture below?

What four weights can be used to balance from 1 to 30 pounds?

What have one eye but still cannot see?

On a certain day, John celebrated his birthday. Two days later, his older twin brother Jacob celebrated his birthday.

Is this even possible? How can it be?

The doctor advised his patient to take a tablet after every fifteen minutes. He gave him five tablets in total.

How much time will he take to have all the five tablets?

You need to complete the maze by entering from the entrance marked below in the figure near the yellow circle, bottom left and leaving from the exit point near the green circle, bottom middle.

Rule of Game: You can move only by exchanging green and yellow circles.