Evolution is the change in the traits of organisms over several generations that relies on natural selection, being the A. how modern organisms descended from older organisms the best option for a definition of evolution in the alternatives.
Global warming / climate change resulting in the melting of glaciers causing a rise in sea level.
I think tissue or a nucleus
The structure in the in the animal cell is the nucleus.
They are educated guesses is not true. A theory must be supported by evidence. Also it is mixed up with the word hypothesis in which case you could say that is an educated guess. Not for scientific theory