Charles Darwin proposed the idea that those individuals best suited to their environment will survive and reproduce, and their t
raits will become more common in a population. He called this idea "natural selection" and explained it as the mechanism for how populations evolve, or change, over time. This idea is widely accepted and has been tested through many experiments that support the idea, but cannot yet be considered proven or a fact. Darwin’s idea is most likely called the great experiment of evolution by natural selection. the hypothesis of evolution by natural selection. the theory of evolution by natural selection. the law of evolution by natural selection.
It's interesting to note that evolution is a <em>proven fact</em>. It is also interesting to note that a <em>theory </em>can be a <em>proven fact. </em>
So, with this in mind, the idea of evolution by natural selection is a <em>theory. </em>A theory cannot become a law!
It also isn't a hypothesis, as it is far beyond that. A hypothesis is just what you think will happen in an experiment.
Given that water is clear and colorless, it seems that it will absorb very little direct radiation from the sun. The sides and the bottom of the pool can however heat it by conduction.