Question

The simplest of all nutrient cycles operating in an ecosystem is ______cycle
A. Carbon
B. Phosphorus
C. Nitrogen
D. Sulphur

Answer 1

Hint: Nutrient cycle is defined as the movement and exchange of organic as well as inorganic matter, flow of energy is noncyclic whereas the flow of mineral nutrients is cyclic.

Complete Answer:
- The major nutrient cycles include carbon cycle, nitrogen cycle, water cycle, sulphur cycle, phosphorus cycle and oxygen cycle. The carbon cycle deals with the exchange of carbon among the biosphere, atmosphere, hydrosphere, geosphere and pedosphere; which is a component of biological compounds as well as makes up many minerals such as limestone. Due to recent human activities the carbon dioxide percentage has increased in the atmosphere that has caused disturbance to the carbon cycle.
- Phosphorus cycle deals with the movement of phosphorus through lithosphere, biosphere and hydrosphere, unlike carbon phosphorus that does not occur in the atmosphere. Phosphorus is required by plants for growth but since it is lost in runoff phosphorus fertilizers are used which also hampers the phosphorus cycle.
- Nitrogen cycle deals with the movement of nitrogen which cycles among the atmosphere, marine and terrestrial ecosystem. Human interventions such as use of nitrogen fertilizer and combustion of fossil fuels disturbs the nitrogen cycle. Sulphur cycle deals with the movement of sulphur among water, air and living systems.
- Sulphur is an important constituent of proteins and also serves as a cofactor in various microbial metabolic processes. Among the four cycles the simplest is the phosphorus cycle since phosphorus exists in only a single form in the entire cycle.

So the correct option is B) Phosphorus.

Note: Nutrient cycle is important in maintaining the ecological balance of the mineral nutrients. It helps in the sustenance of a wide range of organisms who depend on different forms of these nutrients.