Changes in the direction of Earth’s axis and changes in the angle at which it tilts affect the severity of

Which mantle is under the crust the upper mantle or the lower mantle i think it's upper let me know if i'm right

The energy needs of a human population are not affected by

Acell in the human nervous system whose primary function is to form myelin and the blood-brain barrier, respond to injury, remove debris, and enhance learning and memory is called a(n) cell.