Which one among the following statements is not correct?

Statement 3 is incorrect because the mantle is not composed of the heaviest materials of the Earth. The Earth's interior is differentiated by density; the core, composed primarily of iron and nickel, contains the heaviest materials. The mantle consists of silicate rocks rich in iron and magnesium, with densities ranging from 2.9 to 5.7 g/cm³, which is significantly lower than the core's density [2]. Statement 1 is correct as the Mohorovicic discontinuity (Moho) separates the crust and mantle [4]. Statement 2 is correct because the mantle holds approximately 67% (more than two-thirds) of the Earth's total mass and 83% of its volume [2]. Statement 4 is correct as the inner core is a dense solid, while the outer core is liquid.

Sources

1. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 4: Earths Interior > The Mantle > p. 54
2. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 4: Earths Interior > The Mohorovicic (Moho) Discontinuity > p. 53
3. [4] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 4: Earths Interior > 4.1. The Internal Structure of The Earth > p. 52