This parasite lives inside the human body.

He is an expert in parasitology and conducts many researches.

He found out that there was a foreign object inside his body.

Parasitism is a part of nature and a form of interaction between organisms.

The insect lives by parasitizing plants.

Humans can make mistakes.

This world where people live is beautiful, and sometimes harsh.

This old document details the lifestyle of humans.

He is living a simple life.

There are various kinds of insects in the garden.