I know it’s a lot but my teacher is not doing so well and it’s hard to learn that way

Need an answer asap 45 points and brainlest to the first person to answer why do scientific theories, such as biological and chemical evolution, represent the strongest explanation of the changes observed in the fossil record. must be in sentence form how can scientific theories on evolution and the fossil record change over time? must be in sentence form

Me with these questions image attached

There are fewer than 100 naturally occurring elements in the universe, but there are millions of different unified substances. explain how this can be true.