The appropriate answer is a. the temperature is high enough but pressure low enough to melt iron. The earth's core is composed of two layers; the inner and outer core. Both layers are composed mainly of iron and nickel. The main difference between the two layers is that the inner core is solid and the outer core is liquid. The inner core is solid because of the pressure created by the overlaying layers; the outer core, mantle and the crust. The inner core is however hotter than the outer core.
D the solar system is much smaller than the Milky Way galaxy
Similarities :Both alluvial fans and deltas deposit sediment.
Difference:
A delta forms when a river empties into a larger body of water. An alluvial fan forms on land where a river emerges from a mountainous area and flows out onto a more gently sloping plain. The decrease in slope causes the river to decelerate and deposit sediment, forming an alluvial fan.
