Which tiny animal is described as living in water biomes and capable of surviving without water for decades?

Which tiny animal is described as living in water biomes and capable of surviving without water for decades?

• A. Tardigrade
• B. Dolphin
• C. Krill
• D. Plankton

Answer: (A)

The key idea is extreme desiccation tolerance in a tiny water-dwelling animal. Tardigrades live in water films on mosses and in fresh water, and when their environment dries out they can curl into a compact, nearly dormant state called a tun. In this form their metabolism slows to almost nothing, allowing them to survive for years—even decades—without liquid water. When moisture returns, they rehydrate and become active again. That combination of living in a moisture-rich microhabitat and enduring long dry spells is what makes tardigrades the best answer. The other options are aquatic and require water to live, so they don’t endure such prolonged dry conditions.

The key idea is extreme desiccation tolerance in a tiny water-dwelling animal. Tardigrades live in water films on mosses and in fresh water, and when their environment dries out they can curl into a compact, nearly dormant state called a tun. In this form their metabolism slows to almost nothing, allowing them to survive for years—even decades—without liquid water. When moisture returns, they rehydrate and become active again. That combination of living in a moisture-rich microhabitat and enduring long dry spells is what makes tardigrades the best answer. The other options are aquatic and require water to live, so they don’t endure such prolonged dry conditions.