The inner core of Earth is composed primarily of iron and a smaller amount of nickel. This is based on scientific studies and observations of Earth's seismic waves and magnetic field.

Composition of the Inner Core:
The inner core is the deepest layer of Earth, located at the center and surrounded by the outer core. It is believed to have a solid composition, despite the extreme temperature and pressure conditions. The main component of the inner core is iron, which makes up about 85% of its composition. Nickel makes up the remaining 15%.

Evidence from Seismic Waves:
Seismic waves generated by earthquakes provide valuable information about the structure of Earth's interior. P-waves (primary waves) and S-waves (secondary waves) travel through different materials at different speeds. Scientists have observed that when seismic waves pass through the inner core, there is a significant increase in the velocity of P-waves compared to S-waves. This suggests that the inner core is solid, while the outer core is liquid.

Iron-Nickel Alloys:
The presence of iron and nickel in the inner core is consistent with the composition of iron-nickel alloys found in meteorites. These alloys have similar densities and magnetic properties to the inner core, supporting the idea that Earth's core contains iron and nickel.

Magnetic Field:
Earth's magnetic field is generated by the movement of molten iron in the outer core. The presence of iron in the inner core contributes to the overall magnetic properties of Earth. The solid inner core, surrounded by the liquid outer core, helps maintain the stability and strength of the magnetic field.

Conclusion:
In conclusion, the inner core of Earth is primarily composed of iron, accounting for approximately 85% of its composition. Nickel makes up the remaining 15%. This composition is supported by evidence from seismic waves, the similarity to iron-nickel alloys in meteorites, and the role of iron in Earth's magnetic field.