The answer is most likely "vascular system". Xylem tissue is a part of a plant's vascular system. Which is mostly responsiple for transportation (of water, food etc.) in a plant. The vascular system of plants is made of two tissues. One is Xylem and the other is Phloem. Phloem transports food from leaves to all other parts of the plant. And Xylem transports water and minerals (which are dissolved in the water) to the leaves.
So if you remove the <u>Xylem</u> tissue from a plant, its vascular system will be affected.
So the the main forces that keep the water on the surface of the planet are to do with plate tectonics. If the plates were to stop moving, the water probably would eventually be absorbed into the interior, although this process would take a very long time indeed.
The tundra has little variation in temperatures
Viruses are not made out of cells, they can't keep themselves in a stable state, they don't grow, and they can't make their own energy. Even though they definitely replicate and adapt to their environment, viruses are more like androids than real living organisms.
