The phenomenon by which a farmland that is left to fallow for several years develops into a forest is called

Step 1: Analyze the question The question describes a farmland that is abandoned (left fallow) and, over several years, gradually changes into a forest. We need the term for this gradual, orderly change in a community.

Step 2: Explain the concept Ecological succession is the gradual, orderly, and predictable replacement of one plant community by another over time until a stable community, called the climax community, is reached.

For farmland left fallow, the typical sequence is:

• Bare or cleared land → grasses and herbs (pioneer species)
• → shrubs and small plants
• → fast-growing trees
• → mature forest (climax community)

Because the soil is already present, this is called secondary succession.

Step 3: Check each option

• A. Succession: Correct. It describes the gradual change from farmland to forest.
• B. Afforestation: This is the deliberate planting of trees by people on land that had no forest. The question describes a natural process, so it does not fit.
• C. Population: This is a group of organisms of the same species living in an area. It is not a process.
• D. Colonization: This is the arrival and establishment of organisms in a new area. It is only one stage within succession, not the whole process of change.

Step 4: Answer The correct option is A. Succession.

Exam tip: Remember the keywords "gradual change", "over time", and "one community replaced by another". They point to succession. If the question says "deliberate planting of trees", think afforestation instead.