How are the upper and lower parts of the mantle the same? How are they different?

Explained

Explanation:

Scientist have divided the second layer of Earth's Surface into two parts those are Upper and Lower mantle.

Although both the layer are almost similar but they do have some minor difference that distinguish the two layers. The upper mantle has Olivine (a very special rock), compounds with silicon dioxide and a substance called Peridotite

Lower mantle is more solid than the upper mantle, it has a lot of Olivine rock, iron, magnesium and many silicate compounds. therefore, its density is higher.