ACCorDing to thE mArs thEory, why DoEs thE moon ContAin littlE iron
A．thE moon FormED From piECEs oF EArth's Crust.
B．thE moon wAs struCk By AnothEr plAnEt.
C．thE moon's Composition rEsEmBlEs thAt oF mArs.
D．thE moon's minErAl ContEnt hAs ChAngED ovEr tim