premise: preventing something decreases the amount of that something sent2: water does not easily flow on a flat surface sent3: water causes soil and rock erosion sent4: a mountain / hill is a kind of environment sent5: a slope is a part of a mountain / hill sent6: building terraces increases the amount of terraces in an environment sent7: water flows down a slope sent8: terraces change slopes into a series of flat steps.
hypothesis: steam can be used to cook food by transferring heat to the food