My younger brother had an appendectomy yesterday.

He decided to undergo sex reassignment surgery.

He likes to take a walk in the park at dusk.

Echinoderms are a type of marine life, many of which have star-shaped bodies.

His skin is very white because of albinism.

This butterfly valve is used to control the flow of fluid.

Diseases of the mitral valve greatly affect the function of the heart.

This check valve has the role of preventing water from flowing backwards.

We should always remember the power of Kannon in difficult times.

This ancient proverb, 'know the other side and yourself, and you will not be in danger in a hundred battles', teaches us the importance of understanding ourselves and others.