About 21% of Earth's atmosphere is composed of oxygen. Oxygen can combine with other substances. The chemical reaction
of oxygen with other substances is called oxidation and it is a source of chemical weathering. The building on the left has
undergone oxidation. Compare the picture on the left with the picture on the right. The building has changed. The rock has
changed much like the building.
Formulate how the rock on the right has changed over time.
Chemical weathering has happened due to acid rain in the area.
Oxygen has chemically reacted with minerals in the rock; oxidation has
occurred.
Water in the atmosphere has caused the rock to rust; it has physically
weathered.
Physical weathering has taken place and the rock is broken down into
smaller pieces.

The movement of tectonic plates in two different locations is shown below: two blocks labeled location a and location b are shown. at location a the top layer of the block shows two horizontal arrows pointing towards each other. small dunes are shown in the middle between the two arrows. the block labeled b has a vertical line in the middle. on the left of the line there is an arrow pointing down. on the right of the vertical line there is an arrow pointing up which statement is most likely true? subduction may occur in both locations. earthquakes may occur in both locations. subduction may occur in location a only and a volcanic eruption may occur in location b only. an earthquake may occur in location a only and a volcanic eruption may occur in location b only.

Which properties describe all matter?

1. the is the thinnest part of the earth. 2. the is the thickest part of the earth. 3. what metals are mentioned in the text?