Which of the following statements is true?

1. The mantle of the earth is made of solid nickel and iron.

2. The crust of the earth is made of solid nickel and iron.

3. The inner core is made of solid nickel and iron.

The inner core of earth is made up of nickel and iron

this is the correct one

3. The inner core is made of solid nickel and iron.

Explanation:

This is the statement that best reflects the reality of the Earth's composition. The inner core of the Earth is made of solid nickel and iron. Moreover, this is the hottest part of the planet. In fact, it is considered to be about the same temperature as the surface of the Sun. We owe the discovery of the inner core to Danish seismologist Inge Lehmann.