Temperature difference and Earth's tilt
Answer: We are evolving to the environment, and the changes around us. And those that don't die
Explanation:
They put pressure on us to adapt in order to survive the environment we are in and reproduce. It is selection pressure that drives natural selection ('survival of the fittest') and it is how we evolved into the species we are today. Genetic studies have demonstrated that humans are still evolving.
Lava is the liquid form of a rock, but i don't believe that it is a rock itself......
