The correct answer is: A. Carbon dioxide
Oxygen is a gas that is essential for life. It is used in cellular respiration, which is the process by which cells convert food into energy. Oxygen is also used in the formation of ozone, which protects the Earth from harmful ultraviolet radiation.
The Earth’s atmosphere contains about 21% oxygen. This oxygen comes from two main sources:
- Photosynthesis: Plants use sunlight to convert carbon dioxide and water into oxygen and glucose.
- Respiration: Animals and other organisms breathe in oxygen and use it to break down food into energy. The waste product of this process is carbon dioxide.
Carbon dioxide is also released into the atmosphere from natural sources, such as volcanoes and forest fires. However, human activities, such as burning fossil fuels, are the main cause of the increase in atmospheric carbon dioxide levels.
The increase in atmospheric carbon dioxide is a major contributor to climate change. Climate change is causing the Earth’s temperature to rise, which is leading to a number of changes, such as more extreme weather events, rising sea levels, and melting glaciers.
It is important to reduce our reliance on fossil fuels and switch to renewable energy sources, such as solar and wind power. We also need to plant more trees, as trees absorb carbon dioxide from the atmosphere.
- Option B: Carbonates absorbed from soil are not a source of oxygen. Carbonates are compounds that contain carbon and oxygen. They are found in rocks and soil. When carbonates are dissolved in water, they release carbon dioxide gas.
- Option C: Oxides of minerals are not a source of oxygen. Oxides are compounds that contain oxygen and another element. They are found in rocks and minerals. When oxides are heated, they release oxygen gas.
- Option D: Water is not a source of oxygen. Water is a compound that contains hydrogen and oxygen. It is essential for life, but it does not contain oxygen that can be used by organisms.