Final answer:
The slash-and-burn technique is known as shifting cultivation, a form of agriculture used in nutrient-poor tropical rainforest climates, which requires low labor and is energy-efficient. It involves clearing and burning forest areas to enrich the soil for farming.
Step-by-step explanation:
Also known as slash-and-burn, shifting cultivation is a type of subsistence agriculture that is commonly found in warm, wet tropical climates. The correct answer to the question is (d) Shifting cultivation. Shifting cultivation is a farming practice often employed in rainforest regions where soils are nutrient-poor due to excessive rainfall and leaching. To enrich the soil, farmers will clear an area of forest, let the vegetation dry, and then burn it. The ash provides nutrients to the soil, allowing for cultivation until the fertility again declines. Once a plot is exhausted, it is left to lie fallow and the process is repeated elsewhere.
Shifting cultivation is sustainable in regions where population densities remain low. It is energy-efficient because it requires minimal labor for a return in crops. In the Americas, plants like corn, beans, and squash are commonly cultivated together in this system, using what's known as the three sisters technique, exemplifying an ingenious use of agricultural biodiversity.