Regina conducted an investigation to determine whether earthworms add nutrients to soil. She used two pots of soil. She added three earthworms to the first pot. She did not add any earthworms to the second pot, which was the control. Regina tested the nutrient levels of the soil in both pots after two weeks. What type of investigation is Regina conducting?

descriptive
comparative
experimental
procedural

Astone is thrown with a speed v0 and returns to earth, as the drawing shows. ignore friction and air resistance, and consider the initial and final locations of the stone. which one of the following correctly describes the change δpe in the gravitational potential energy and the change δke in the kinetic energy of the stone as it moves from its initial to its final location? options a.δpe = 0 j and δke = 0 j b.δpe is positive and δke is negative c.δpe = 0 j and δke is positive d.δpe is negative and δke is positive e.δpe = 0 j and δke is negative