I'm fed up with his pranks.

His pranks are causing trouble to his classmates.

Gender identity refers to the gender that each individual recognizes themselves as.

His talent is immediately noticeable.

He is facing many difficulties due to gender identity disorder.

He decided to change his character.

If you rephrase that complex theory in simpler terms, it's just common sense.

This apple contains poison.

Hypervitaminosis occurs when the intake of vitamins is too high.

Osamu is sleeping and snoring.