Question

Oxygen is returned to the atmosphere mainly by __________
(a) Burning of fossil fuels
(b) Respiration
(c) Photosynthesis
(d) fungi

Answer 1

Hint: Animals draw oxygen from the atmosphere for the breathing process. By using autotrophic substances such as green plants to synthesize nutrients such as glucose and to release oxygen in the presence of sunlight to carbon dioxide and water. Oxygen is then returned to the atmosphere.

Complete Answer:
Sunlight is used by green plants to generate carbon dioxide and water nutrients. Photosynthesis in plants typically requires chlorophyll and as a by-product produces oxygen. Any oxygen is produced when sunlight interacts in the atmosphere with water vapor. The energy, carbon dioxide, and water are released by the oxidation of carbohydrates.
$ 6C{ O }_{ 2 }+6{ H }_{ 2 }O\longrightarrow { C }_{ 6 }{ H }_{ 12 }{ O }_{ 6 }+6{ O }_{ 2 }+6{ H }_{ 2 }O$

Additional Information:
The cycle of oxygen is the cellular oxygen cycle.
-Oxygen cycling is a very complex operation.
-In several combinations and sources of chemical oxygen takes place.
-It combines to form nitrates with nitrogen.
-They are often used to form various oxides, including iron oxides, aluminum oxide, and others in conjunction with many other elements and minerals.
-During photosynthesis, carbon dioxide is absorbed by plants.
-The decomposition of water molecules by sunlight during photosynthesis creates a large amount of oxygen.
-Air absorbs oxygen and discharges carbon dioxide into the environment from humans to animals.
-Again, photosynthesis and processes are replicated by this carbon dioxide, consumed by plants.

So, the correct answer is, “Photosynthesis”

Note:
- The combustion of fossil fuels contributes to carbon dioxide pollution in the atmosphere.
-The break-up in our body of glucose with or without oxygen to create so-called breathing capacity. Breathing is the water cycle process.
-The molten eukaryotic cells are multicellular. They are a saprophytic body and feed on the dead organic matter.