.Why is topsoil darker than all other levels of soil?

Which property of fossils allow scientists to determine the relative rock ages..

Alfred pushes on a heavy box, but cannot move it. the box has a lot of inertia motion friction gravity

Which of these questions might a character ask if the conflict is man versus self? a. which path should i take to better myself? b. which boulder will be too heavy for me to carry? c. which friend is going to ditch me today? d. all of the above