descriptionwords that describe the characteristics of rocks:
“Most rocks at the Earth's surface are formed from only eight elements (oxygen, silicon, aluminum, iron, magnesium, calcium, potassium, and sodium), but these elements are combined in a number of ways to make rocks that are very different.”
“Geologists classify rocks in three groups, according to the major Earth processes that formed them. The three rock groups are igneous, sedimentary, and metamorphic rocks.”What is being described?
What is important to know about this subject?
chronological order“begin with,” “first”:
“A rock collection might begin with stones picked up from the ground near your home. These stones may have limited variety and can be replaced later by better specimens. Nevertheless, this first step is helpful in training the eye to see diagnostic features of rocks.”What events or steps are described?
Do these things need to occur in a particular order?
