Final answer:
Plants perform photosynthesis, where they convert H₂O and CO₂ into glucose and release oxygen. This process is essential for their growth and the sustenance of oxygen-dependent life on Earth.
Step-by-step explanation:
Plants take in molecules of H₂O (water) and CO₂ (carbon dioxide) and use them in a process known as photosynthesis. This process converts these molecules into glucose (C₆H₁₂O₆), a type of sugar, and releases oxygen (O₂) as a byproduct. The glucose produced during photosynthesis serves as an essential energy source for the plant, enabling it to grow, reproduce, and carry out various life processes. Moreover, the oxygen released is vital for animal life on Earth, including humans.
Specifically, plants capture energy from sunlight through their leaves and use this energy to transform CO₂ and H₂O into glucose. This process adds to the plant's biomass, as the carbon from CO₂ becomes part of the plant's structure in the form of glucose and other organic molecules. Consequently, plants are fundamental not only for producing their own energy but also for sustaining the Earth's atmosphere and the life that depends on it.