P waves can travel through Earth's outer core, but S waves cannot. Because of this, scientists know
A.
the outer core is solid.
B.
the outer core is liquid.
C.
the outer core is made of iron.
D.
the outer core is made of rock.
The outer core is about 1,400 miles thick, and it's made mostly of a combination (called an alloy) of iron and nickel, along with small amounts of other dense elements like gold, platinum, and uranium.
