What is the meaning of virus?

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

Where can dna be found in a prokaryotic cell

Which example would the nurse consider to be a part of systems thinking theory?