He understands the risk of being infected with semen that contains HIV.

The problem of introduced species can potentially disrupt the balance of ecosystems.

Many native species live in this park.

I use koji starter to make homemade miso.

What is the specific epithet of this plant?

The doctor examined his semen sample.

It is important to learn the history of the World War.

The volume ratio of this container is 1:2.

He is troubled by chronic headaches.

Sekibune is a type of boat that was used for military purposes historically.