Reading Comprehension Related

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Photosynthesis is a process used by plants, algae, and certain bacteria to convert light energy into chemical energy stored in sugar molecules. This process is fundamental to life on Earth as it provides the primary source of energy for nearly all organisms. The energy is captured from sunlight by a pigment in the plants called chlorophyll, which gives plants their green color.
During photosynthesis, carbon dioxide from the air and water from the soil react in the presence of light to form sugars and oxygen. The oxygen is released into the atmosphere, which is crucial for the survival of most life forms on Earth. The sugars produced are used by the plant for energy and growth, storing excess energy as starch.
The process occurs in two main stages: the light-dependent reactions and the Calvin cycle. In the light-dependent reactions, energy from sunlight is absorbed by chlorophyll and converted into stored chemical energy in the form of ATP and NADPH. The Calvin cycle uses the ATP and NADPH produced in the light-dependent reactions to convert carbon dioxide into glucose.
Photosynthesis not only sustains plant life but also maintains the atmospheric oxygen levels and is a key factor in the carbon cycle, helping to regulate Earth's climate.

Which gas is crucial for the survival of most life forms and is released during photosynthesis?

  • A. Nitrogen
  • B. Carbon dioxide
  • C. Oxygen
  • D. Hydrogen
Correct Answer: C

Rationale: During photosynthesis, oxygen is crucial for the survival of most life forms and is released into the atmosphere. Oxygen is a byproduct of the photosynthetic process, where carbon dioxide and water react in the presence of light to form sugars and oxygen. This released oxygen is essential for the respiration of many living organisms, making it a critical component for their survival. Without the oxygen released during photosynthesis, many organisms would not be able to carry out cellular respiration, which is vital for their energy production and survival.