Here are the answers to the questions based on the given soil characteristics:
9. The dominant clay mineral is:
- b) Montmorillonite
- Montmorillonite is known for having a high plasticity index (PI) and can exhibit slickensides due to its expansive nature when wet. Strong structural characteristics are also associated with this mineral.
10. The strong structure is an indication of:
- c) physical stability
- A strong soil structure indicates that the soil has good aggregation and stability, which promotes aeration, but the use of "strong structure" typically refers to physical stability rather than the conditions of saturation or aeration.
11. Water:
- a) high in the wet and low in dry state
- Generally, water content is high when the soil is wet, and lower when it is dry, especially relevant in soils with high plasticity.
12. Root development in the soil will be:
- a) restricted by the slickensides
- Slickensides can create a hard, compact surface that makes it difficult for roots to penetrate, thus restricting root development.
13. Kaolinite clay is:
- b) physically active and chemically inactive
- Kaolinite is relatively stable and does not expand or contract significantly with moisture changes (physically inactive), but it has limited cation exchange capacity, meaning it is chemically less active compared to smectites like montmorillonite.
These answers are based on the typical properties of these materials and soil behavior.