Q. In the structure of planet Earth, below the mantle, the core is mainly made up of which one of the following?
Answer: Iron
Notes: Earth's core, located below the mantle, is primarily composed of iron (Fe), making it the most significant element in this region. The core is divided into two parts: the outer core, which is liquid iron mixed with nickel and lighter elements, and the inner core, which is solid iron under extreme pressure. Iron comprises approximately 85-90% of the core's composition, with nickel and smaller amounts of other elements like sulfur and oxygen. This iron-nickel composition is why Earth's core is often called the nife layer. The extreme temperature and pressure conditions enable Earth's magnetic field generation through the movement of liquid iron in the outer core.