The correct answer is: A. Ecosystem service
Ecosystem services are the benefits that humans obtain from ecosystems. These benefits include provisioning services such as food, water, and fiber; regulating services such as climate regulation, flood control, and water purification; cultural services such as recreation, aesthetic enjoyment, and spiritual enrichment; and supporting services such as nutrient cycling and soil formation.
Biological control is the use of natural enemies to control pests. Biological control can be used to control a wide range of pests, including insects, mites, nematodes, weeds, and plant diseases.
The greenhouse effect is the process by which the Earth’s atmosphere traps energy in the form of heat. This heat is what keeps the Earth’s temperature at a level that is suitable for life. However, human activities such as burning fossil fuels are increasing the amount of greenhouse gases in the atmosphere, which is causing the Earth’s temperature to rise.
Biosphere balancing is the process by which the Earth’s ecosystems maintain a stable equilibrium. This equilibrium is essential for life on Earth. However, human activities such as deforestation and pollution are disrupting the Earth’s ecosystems, which is causing the biosphere to become unbalanced.
In conclusion, the correct answer is A. Ecosystem service.