What is the next shape from answers A, B, C, and D figure?

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

Name the three-letter word that can complete the below words?

A) L O _ _ _ E
B) E D U _ _ _ E
C) _ _ _ E R
D) _ _ _ T L E

John was running from 40 thieves. John has got 3 gold boxes which weigh as 4kg, 2kg, and 1kg respectively. A witty man asked John to stay with him for seven days in exchange for 1kg gold per day. John needs to stay there for seven days and also do not want to give the witty man any advance. How can John pay for his seven days stay?

A mile-long train is moving at sixty miles an hour when it reaches a mile-long tunnel. How long does it take the entire train to pass through the tunnel?

Why is 6 afraid of 7?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

What is at the end of a rainbow?

Eight of us go fourth, not back, to protect our king from an attack. What are we?

What do you see in the image below