Answer:
The solidifying/cooling and crystallizing of magma causes igneous rocks to form.
Explanation: <em>The hypothesis is a prediction, but it involves more than a guess. Most of the time, the hypothesis begins with a question which is then explored through background research. It is only at this point that researchers begin to develop a testable hypothesis.</em>
(Unless you are creating an exploratory study, your hypothesis should always explain what you expect to happen)
When trying to clean muddy, dirty river water, FILTRATION would work best
