Question

The nutrient cycle that has largest reservoir in the atmosphere is
A.Carbon cycle
B.Nitrogen cycle
C.Potassium cycle
D.Phosphorus cycle
E.Water cycle

Answer 1

Elemental components of organic matter are cycled through the biosphere and this process is called biogeochemical cycle. Carbon, nitrogen, hydrogen, oxygen, phosphorus, and sulfur are conserved and recycled in the atmosphere, on land, in water, or beneath the earth’s surface.

Complete answer:
A nutrient cycle is the movement, exchange of organic and inorganic matter back into the production of living matter. The process is regulated by the food web pathways previously presented, which decompose organic matter into inorganic nutrients. Nutrient cycles occur within ecosystems which are:

1.Water cycle: Over two thirds of the Earth's surface is roofed by water. It forms a very important component of most life forms. Vast quantities of water cycle through Earth's atmosphere, oceans, land and biosphere. This cycling of water is named the water or hydrological cycle. The cycling of water is very important in determining our weather and climate, supports plant growth and makes life possible.
a.Evaporation: Most water evaporates from the oceans, where water is found in highest abundance. However some evaporation also occurs from lakes, rivers, streams and following rain.
b.Transpiration: The water loss from the expanse of plants. Transpiration accounts for a large 50% of land-based evaporation, and 10% of total evaporation.
c.Evapotranspiration: The processes of evaporation and transpiration are often collectively observed as evapotranspiration.
d.Condensation: The method by which water vapor is converted back to liquid is called condensation.
e.Precipitation: Water returns to Earth through precipitation within the style of rain, sleet, snow or ice. When rain occurs because of precipitation, most of it runs off into lakes and rivers while a big portion of it sinks into the bottom.
f.Infiltration: the method through which water sinks into the bottom is thought as infiltration and is set by the soil or rock type through which water moves. During the method of sinking into the Earth's surface, water is filtered and purified. Counting on the soil type and also the depth to which the water has sunk, the bottom water becomes increasingly purified: the deeper the water, the cleaner it becomes.

2.Oxygen cycle: Oxygen is one in every of the most gases found within the air, together with nitrogen. Oxygen is recycled between the air and living organisms within the following ways:
a.Breathing and respiration: Organisms like animals and plants soak up oxygen from the air during breathing and gaseous exchange processes. The oxygen is employed for internal respiration to release energy from organic nutrients like glucose.
b.Photosynthesis: During photosynthesis, plants absorb dioxide from the air to synthesise sugars, and release oxygen. There is a complementary relationship between photosynthesis and respiration therein the previous produces oxygen and therefore the latter consumes oxygen.

3.Carbon cycle: Carbon is the basic building block of all organic materials, and thus, of living organisms. Most of the carbon on earth is found within the crust. Other reservoirs of carbon include the oceans and atmosphere. Carbon moves from one reservoir to a different by these processes:
a.Combustion: Burning of wood and fossil fuels by factory and auto emissions transfers carbon to the atmosphere as $CO_{2}$.
b.Photosynthesis: carbonic acid gas is haunted by plants during photosynthesis and is converted into energy rich organic molecules, like glucose, which contains carbon.
c.Metabolism: Autotrophs convert carbon into organic molecules like fats, carbohydrates and proteins, which animals can eat.
d.Cellular respiration: Animals eat plants for food, taking on the organic carbon (carbohydrates). Plants and animals break down these organic molecules during the method of metabolic process and release energy, water and $CO_{2}$. Greenhouse emission is returned to the atmosphere during gaseous exchange.
e.Precipitate: $CO_{2}$ within the atmosphere also can precipitate as carbonate in ocean sediments.
f.Decay: carbonic acid gas is additionally released into the atmosphere during the decay of all organisms. Photosynthesis and gaseous exchange are the most carbon cycling processes involving living organisms.

4.Nitrogen cycle: Nitrogen makes up most of the gas within the atmosphere. It's important to living organisms and is employed within the production of amino acids, proteins and nucleic acids. Nitrogen gas present within the air isn't available to organisms and thus needs to be made available during a form absorbable by plants and animals. Only some single-cell organisms, like bacteria can use nitrogen from the atmosphere directly. For plants, nitrogen must be became other forms, eg. Nitrates or ammonia.

Hence, the correct answer is option (B)

Note: Human activity releases nitrogen into the environment by: combustion of fossil fuels, and also the use of artificial fertilizers in agriculture. Atmospheric nitrogen is related to several effects on earth’s ecosystems, including the assembly of acid precipitation and gas, potentially causing global climate change. A serious effect from fertilizer runoff is saltwater and freshwater eutrophication within which nutrient runoff causes the surplus growth of microorganisms, depleting dissolved oxygen levels and killing ecosystem fauna.