NEED ASAP! Why do geologists think earths core contains mostly iron?

A. Other orbiting bodies contain more iron than earth's crust does.
B. The moon's crust contains far less iron than earth's crust.
C. The crust contains no nickel.
D. The crust contains a mixture of iron and silicon.

weathering - colorado river carves land in arizona to form the grand canyon. cracks form in a sandstone wall surrounding a house. a marble statue near the science museum is changing color due to rainfall

erosion - after a rainstorm, soil and rock piees litter the roadways. the sand dunes in the sahara desert are changing shape.

here's your answer.