Explain why this difference between the inner and outer core's density exists?

Metals and the frequency in which they're found influences a lot since different metals have different densities. Heat also influences a lot since hotter things tend to be less dense though the inner core is more dense.

The inner core is more dense because it's liquid and hotter, and since it's liquid the earth's movement makes it difficult for the inner core to be less denser than it is.

Hope it helped,

BioTeacher101

cramming before a final is bad because it makes a student's stress level higher. students who embrace cramming to get through a final exam week find themselves struggling to perform consistently, once the brain adjusts to prolonged sleep deprivation.

it's c. (to reduce the greenhouse effect/carbon gasses)