27.
A rock inside a building is not likely to be affected by (2 points)

chemical weathering

any of these

biological weathering

mechanical weathering

28.
Fertilizers can put extra nitrogen into coastal waters, which can cause (2 points)

overgrowth of algae that produce toxins

too many fish which depletes oxygen

a change in the water's temperature

the water to become too salty
29.
Name and describe two types of mechanical weathering. (4 points)
writing part

30.If scientists determine the age of a rock to be three billion years old, what else do they know? (2 points)

The rock came from outside the solar system

The rock was part of a comet

The Earth is at least three billion years old

The Earth is younger than three billion years old