Which radioactive isotope might be most useful to date an artifact that was found in a rock layer just above the Cretaceous-Tertiary impact

Which tool is least in predicting weather

The graph indicates the running route for tobias. which best describes his run? from time 0 to 6, he went fast and then slowed down. from time 6 to 10, he was at his slowest. from time 12 to 14, he went very slow. from time 14 to 18, he went toward the starting point.

Which of the four hypothetical substances you investigated would be most harmful to living organisms? 50 points!