Reading Comprehension

Read the passage and answer the question.

The tardigrade, often called the water bear, is a microscopic animal famous for surviving conditions that would kill almost any other creature. When its environment dries out, the tardigrade pulls in its legs and enters a dormant state called a tun, in which its metabolism nearly stops. In this form it can endure extreme heat, freezing temperatures, intense radiation, and even the vacuum of space. Researchers believe a special protein replaces lost water inside the animal's cells, forming a glass-like structure that protects delicate molecules until water returns and the tardigrade revives.