Bob is very young, but he can lift heavy bags without others’ help. He does not fall sick. He can walk, run and play for a long time without breaks. 

Which of the following similes is suitable for describing Bob?
 

The statements that describe Bob clearly indicate that he is strong (like lifting heavy bags, not falling sick, and running and playing for a long time without breaks). Hence, Option 4 (strong as a lion) is appropriate. It indicates that Bob is strong like a lion.