Why must you repeat steps three and four in the scientific method

Jake has a nine month old son. how can he build his self esteem

We found the centripetal acceleration of the earth as it revolves around the sun. compute the centripetal acceleration of a point on the surface of the earth at the equator caused by the rotation of the earth about its axis. (enter the magnitude. the radius of the earth is 6,371 km.)

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