Why do scientists think earths core contains iron

The core consists of a solid inner core and a fluid outer core. The fluid contains iron, which, as it moves, generates the Earth's magnetic field. The crust and upper mantle form the lithosphere, which is broken up into several plates that float on top of the hot molten mantle below.

Explanation:The core consists of a solid inner core and a fluid outer core. The fluid contains iron, which, as it moves, generates the Earth's magnetic field. The crust and upper mantle form the lithosphere, which is broken up into several plates that float on top of the hot molten mantle below.

answer:

key word they didn't invent oxygen.

discover-find (something or someone) unexpectedly or in the course of a search.

invent-create or design (something that has not existed before); be the originator of.