The gas involved in the photosynthesis process is

Question

Accepted Answer

The correct option is 4:
Photosynthesis is the fundamental biochemical process by which green plants, algae, and some bacteria convert light energy, usually from the sun, into chemical energy in the form of glucose (sugar). This process is essential for life on Earth as it produces the oxygen we breathe and forms the base of most food webs. The reaction requires three main components: light energy, water ((H\_2O)), and a specific gas from the atmosphere. The key gas that plants take in through small pores (stomata) on their leaves to serve as the carbon source for building sugar molecules is Carbon Dioxide ((CO\_2)). The overall balanced chemical equation for photosynthesis shows this clearly: (6CO\_2 + 6H\_2O + \text{Light Energy} \rightarrow C\_6H\_{12}O\_6 + 6O\_2). Thus, Carbon Dioxide is the primary gaseous reactant involved.

The incorrect option is 1 (Ozone):
Ozone ((O\_3)) is a gas found primarily in the stratosphere where it forms a protective layer, or in the troposphere where it acts as a pollutant. It is highly reactive and is not used by plants as a reactant for the photosynthesis process. High concentrations of ozone are actually harmful to plants, damaging their leaves and inhibiting their growth.

The incorrect option is 2 (Oxygen):
Oxygen ((O\_2)) is an output or byproduct of photosynthesis, not a gas that is consumed or "involved" as a primary reactant. Plants release Oxygen into the atmosphere after splitting water molecules during the light-dependent reactions. While Oxygen is crucial for cellular respiration, it is the product, not the input, for photosynthesis.

The incorrect option is 3 (Hydrogen):
While Hydrogen atoms are necessary for photosynthesis (they come from the water molecules, (H\_2O)), the elemental gas Hydrogen ((H\_2)) is not consumed from the atmosphere by plants for this process. Hydrogen gas is extremely rare in the atmosphere and is not integrated into the reaction, unlike carbon dioxide.