Which resource use is affected when soil fertility decreases?

Correct answer: Agricultural production

Direct answer: Option A, agricultural production. Soil fertility means the soil's ability to supply plants with nutrients, water and suitable conditions for growth. The reasoning is: lower fertility means fewer nutrients or poorer soil conditions; crops then grow less strongly; yields may fall; food production and food security can be affected. Option A is therefore directly connected to soil use. Option B, ocean tides, are mainly controlled by the gravitational pull of the Moon and Sun, not by farm soil fertility. Option C, sunlight, is an important natural factor for plants, but decreasing soil fertility does not determine whether sunlight exists. Option D, mountain height, is a physical landform feature and does not become lower merely because soil loses nutrients. The question asks what resource use is affected, not what causes fertility loss. Memory cue: fertile soil supports crops; poor soil can reduce harvests.