How do scientists know that the core is made of iron and nickel? The core produces a lot of seismic waves.

Scientists have gathered samples of the core.

Pictures of the core have been taken from satellites.

The core is dense and produces a magnetic field.

The core produces a lot of seismic waves.

Explanation:

There are no samples of Earth’s core accessible for direct measurement, as there are for Earth’s mantle. Information about Earth’s core mostly comes from analysis of seismic waves and Earth’s magnetic field. The inner core is believed to be composed of an iron–nickel alloy with some other elements

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a. an ice age

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