preferred way to answer a question

I'm unsure how you want us to answer the questions "Discuss environmental and soil conditions under which following

soil horizons are most commonly present". Do you simply want us to just define the horizon, or actually go into depth? For example, can you answer the question for say, a Bv horizon?

Well you can discuss the basics of each horizon - like LFH horizon occurs in forests with litter fall, A is a horizon that typically has illuviation of material building up in the B horizon and C horizons are most similar to the parent material.

You can then discuss specifics within the horizons like Ae with a Bf beneath it shows that the environmental conditions are high rainfall that has resulted in the iron washing out of the A horizon and accumulating in the B horizon. In terms of soil conditions you could discuss that there needs to be iron present in the first place - perhaps from the parent material and that the texture of the soil would need to have a relatively even distribution of pore sizes in order to allow for the translocation to occur (if dominated by clay the profile would not allow for movement of cations as they would be held within the micropores).

For the Bv, that is one of the diagnostic horizons for a vertisol - which are dominated by smectite clays. So you should think of environmental examples that would create a high proportion of clay. Precipitation? Primary minerals? Parent material? Weathering? Think about what specific environmental/soil conditions that would cause the agrilipedoturbation (hint: wetting and drying).

Hope this helps.