I BELIEVE the answer is D) 4.
Earth's crust is generally divided into older, thicker continental crust and younger, denser oceanic crust..The crust is made of solid rocks and minerals.
The mantle lies between Earth's dense, super-heated core and its thin outer layer, the crust. The mantle is about 2,900 kilometers (1,802 miles) thick, and makes up 84% of Earth's total volume.
The core lies beneath the cool, brittle crust and the mostly-solid mantle. ... Earth's core is the very hot, very dense center of our planet. The ball-shaped core lies beneath the cool, brittle crust and the mostly-solid mantle.1
It was believed that the magnetic field to be generated deep down in the Earth's core. But the truth is the flow of liquid iron generates electric currents, which produces magnetic fields.
But the truth is no one really knows for certain so the only thing we know is that the spin of the earth is the cause of its magnetic field
Hope this helped :)
Have a great day
It's controversial because the best source of stem cells is a human embryo (an aborted fetus).
