It is known that passive smoking has a negative impact on health.

He is dedicated to the study of immunochemistry.

In Australia, the cane toad is causing a big problem.

People with strong general immunity are less likely to catch a cold.

Mucosal immunity plays a crucial role in protecting our bodies from pathogens.

He swore to protect that secret even at the cost of his life.

He had a narrow escape in that accident.

I can't solve this problem because there are too many numbers.

The police are conducting an investigation at the scene.

Please proceed one by one in order.