Explanation:

The inner core, which is composed mainly of solid iron and nickel, is thought to rotate slightly faster than the rest of the Earth. 

• This has been inferred from the study of seismic waves and is thought to be caused by the Coriolis effect, which results from the Earth's rotation.

• This effect is caused by the centrifugal force that arises from rotation and causes the inner core to rotate faster than the rest of the planet.

• The inner core of the Earth is thought to be composed primarily of iron and nickel, with smaller amounts of other elements such as carbon, silicon, and sulfur.

• The boundary separating the inner core from the outer core is called the Bullen discontinuity, named after the British geophysicist, Dr. John Bullen who first identified it in the 1950s. 

Hence both statements are correct.