Scientists have estimated the density of Earth
A) by averaging the density of several hundred crust samples.
B) by measuring the wobbly rotation of Earth on its axis.
C) by calculating its interaction with nearby celestial objects.
D) by taking a drilling core and averaging the density of those rocks over the depth.
Question 2
Geologists have not studied the composition of the oceanic crust by
A) dragging buckets along the floor to collect sediment and rocks.
B) studying the contents of drill holes.
C) examining aboveground mountain ranges.
D) analyzing earthquake data.
