People in living in areas with steep mountains actually has an advantage when it comes to agriculture because there is already a free and vacant space that can be used to plant crops. In order to develop thesemountains into an area where planting is easily done, the people can create a stair-like structure on the edges of the mountains where they can plant crops that will be used daily and even sold in the market. This practice will be a very good strategy to make use of the steep mountain which is the only available natural resource at the time.
I believe the answer is: they may farm on their lands to have food more accessible
People who live in steep access would most likely have little to no access from the outside world, which make it almost impossible for them to obtain their daily necessities by purchasing it on the store.
Because of this, they need to farm on their land to obtain their daily necessities.
