The answer is the second choice: variation, overpopulation, adaptation
Location 2 is cooler than Location 3 and Location 1 because it's at a higher altitude
They survive without water by entering a special mode, otherwise called as shriveling. They can lose even 95% of water in their body and still live, even though they would look like dead plants, they would actually be alive. In the absence of water, tardigrades use a sugar called trehalose, which becomes their source of life until they find some water.
Answer:
The movement of the replication fork is accomplished by the enzyme helicase, which breaks hydrogen bonds between the paired bases and unwinds the double helix ahead of the advancing DNA polymerase.
