Which isotope dates rocks a billion of years old

When does dna replication(make a copy of itself)?

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

For a comparative or experimental investigation, scientists often make a testable about a scientific question, and then they test it in the investigation. a. control b. hypothesis c. procedure d. system