She was massaging her nape.

He is doing special exercises to strengthen his cervical muscles.

He trains his deltoid muscles at the gym every day.

He has strong masseters, so he can easily bite through hard food.

If your muscles of mastication are strong, you can chew food more efficiently.

If the balance of the triple burner is disrupted, you may feel unwell.

He made a model of a triangular pyramid.

Isami is my best friend.

The three states of matter are solid, liquid, and gas.

My younger brother is currently in his third year of high school, preparing for university entrance exams.