Stress

Bite his tongue

Toadstool (poisonous mushroom)

Senelity

Laughed too much

Sleeping pills

Died too much

All questions correct: stupid

3 errors or less: drink spinach juice

3 errors or more: drink spinach juice

4 errors or more: instant death

Death by love

Death by shock

Fugu (Blowfish)

Mangaka aptitude, test 2
(Mangaka = cartoonist)

Death by sadness
(this is a pun, it's written "Kanashi", with shi being death, and "Kanashii" is "sad")

Crybaby

Tumor

Mochi Japanese and Chinese rice cake made of glutinous rice. Some senior citizens die while eating mochi due to asphyxiation.

UmeboSHI Shi here is written by death kanji