Which of the following living things can halt their metabolism in reaction to harsh environmental conditions?
A frog
A bear
A tardigrade
A fish
Correct option (c) - A tardigrade
Tardigrades, commonly referred to as water bears or moss piglets, are tiny creatures that can endure harsh environments. One of its amazing traits is the ability to undergo a form of suspended animation known as cryptobiosis when exposed to extreme climatic circumstances like high radiation levels, dry environments, and freezing temperatures.
The tardigrade's metabolism effectively stops during cryptobiosis, allowing it to go for extended periods of time without food or water. The tardigrade can rehydrate and continue its regular metabolic processes once the environment is more favorable. Fish, frogs, and bears, on the other hand, cannot go into cryptobiosis and halt their metabolism.
Option c is the correct answer.