A seed begins the germination process when it gets the , temperature, and oxygen that it needs. As the seed absorbs water, the tiny seedling inside of the seed begins to grow and expand, against the seed coat. The seedling must exert enough to break through the seed coat and through the soil. There must also be enough for the shoot to move against the force of . is the force that attracts all objects with to each other. occurs when a plant turns toward or away from the pull of gravity. Because of geotropism, plant grow toward the pull of gravity as they push deeper into the soil. The plant grow away from the pull of gravity as they break through the soil and the stem grows into the air. Through the forces resulting from pressure and geotropism, plants are able to do a lot of . Plant roots can break apart rock and concrete as they grow the pull of gravity. A seed can break apart rock-hard soil as it expands due to turgor pressure and the of the seedling emerging from the seed coat.