Which one of the following is not internal force?Question 15Answera.Denudationb.Faultingc.Volcanic eruptiond.Folding

To determine which option is not an internal force, we need to understand the different geological processes each term refers to.

1. Denudation: This is a process of wearing away the Earth's surface which involves both weathering and erosion. It is primarily a surface process rather than an internal force.

2. Faulting: This is an internal force involving the breaking and displacement of the Earth’s crust.

3. Volcanic eruption: This is also an internal force where molten rock (magma) escapes from the interior of the Earth to the surface.

4. Folding: This refers to the bending of rock layers due to internal forces affecting the Earth's crust.

Conclusion

From the analysis, the correct answer is a. Denudation, as it involves surface processes and is not classified as an internal geological force.