7. Which of the following units is youngest? A, H, I, M, K 8. Which of the following units is oldest? L, M, G, F, J Use this geologic cross-section (x-section 2) to answer the following questions. Layers A, B, C, D, E, F, G, H, and I are sedimentary layers. L and K are plutonic igneous intrusions. M and J are faults. The wavy line is an unconformity. Click to enlarge image Question 7 Which of the following units is youngest? A , H , I , M , K.